Assault on the Control Room (Level)

Assault on the Control Room is the fifth campaign level in Halo: Combat Evolved. It is the longest campaign level in Halo: Combat Evolved.

The level follows the Master Chief on a mission to reach the Control Room of Installation 04. The Covenant are deployed in greater numbers and in a superior force than previously seen in the game, using Wraiths, Ghosts and Banshees.

The majority of the level is set in a snowy, outdoor environment. Although the level seems to be natural, there are networks of tunnels and elevators built by the Forerunners that connect sections of the constructs into the Control Room.

The level is known for its variety and well roundedness. It allows the player to use every weapon and vehicle in the game (except the Shotgun), and is the only stage in Halo: Combat Evolved that allows Master Chief to use a Scorpion tank. Although the level is famous for its snowy outdoor battles and large bridges, there are also a variety of indoor skirmishes, including standoffs with Zealot Elites. There is a mix of vehicle, long-range, and close quarters combat. The player is assisted by a handful of Marines after their Pelican crashes, but the level is mostly a solitary experience.

At the end, Master Chief reaches the control room and Cortana interfaces with the computers. She is horrified to learn that Halo houses the Flood, and the weapons cache that Captain Keyes is looking for will lead him straight to the parasite. Cortana elects to stay behind, while Chief rushes off to find Captain Jacob Keyes.

Usable Weapons

 * Pistol
 * Assault Rifle
 * Sniper Rifle
 * Rocket Launcher
 * Frag Grenade
 * Plasma Pistol
 * Plasma Rifle
 * Needler
 * Plasma Grenade
 * Shade

Vehicles

 * Warthog
 * Scorpion Tank
 * Ghost
 * Banshee
 * Pelican (non-drivable)
 * Spirit (non-drivable)
 * Wraith (drivable with mod only)

Cinematic
'''Part 01: I Would Have Been Your Daddy... '''

{Fade in to the interior of a large Forerunner dome, pan down to a long shaft, a Grunt paces on an open platform}

{Close up of the walking Grunt, other Grunts around him are asleep, he stops as he hears jets, he sniffs the air, and yelps as a Pelican rises up in front of him, screams and runs towards the door}

Gameplay
Foe Hammer (O.S.): "This is as far as I can go."

Cortana (O.S.): "Roger that, we can find our way to the Control Center from here."

Foehammer (O.S.): "Good luck, Foehammer out."

{the Pelican hovers at the edge of the platform, the Chief gets out}

(Once you clear the first of the circular rooms)

Cortana:"The Covenant presence here is stronger than I anticipated. They seem to have the entire region secured."

(Once you reach the first bridge)

Cortana:"Interesting... the weather patterns here seem natural, not artificial. I wonder if the ring's environment systems are malfunctioning... or if the designers wanted the installation to have inclement weather. "

''{a Pelican Dropship flies over the bridge. The Covenant forces on the bridge open fire}''

Sergeant (O.S.):"This is Fire Team Zulu requesting immediate assistance from any UNSC forces. Does anyone copy?"

Cortana:"I didn't think there were any human forces left on this part of the ring.... (O.S.) Cortana to Fire Team Zulu, I read you. Fire Team Zulu, this is Cortana. Hold position. We're on our way."

Sergeant (O.S.):"Roger that. Make it quick."

{The Pelican descends to an area below the bridge}

(When you reach the bottom of the chasm and meet up with Fire Team Zulu)

{A large number of Covenant have three Marines with an overturned Warthog cornered. A Covenant Wraith tank fires plasma mortars as Shade turrets and Ghost vehicles strafe the Marines.}

Marine 1:"Glad you could join the party, Sir!"

or

Marine 1:"Master Chief, Sir! Good to see you!"

(When you reach the second group of Marines fighting near the Scorpion and clear the area)

Marine 1:"Enemy forces eliminated. The area's secure."

Marine 2:"Aw, crap. Let's get the hell outta here, man! Somebody call the dropship!"

Sergeant:"You stow that garbage right NOW, mister. You're a Marine, so act like it, dammit! We've got a job to do."

or

Marine 1:"Shut up! Show some backbone, amigo!"

Cortana (O.S.):"Negative, team. No evac available at this time. But the Chief and I could use some assistance."

Sergeant:"Okay, Marines. Time to pay back the Chief for pulling your sorry tails out of the fire. Prepare to move out!" (As you reach the second large open area, where one Wraith hovers on the ice and another lurks on top of the cliff at the far end of the canyon)

(There are at least three choices here-how the game chooses which one to play is unknown. It seems to be random, as a checkpoint right before this area will result in different dialogues after restarting.)

(Type 1)

Marine 1:"Bloody hell! Enemy forces have armor support...it's time to earn our pay."

Cortana:"The Covenant placed their tanks to defend the entrance to the tunnel."

(Type 2)

Marine:"Enemy mortar tanks sighted at my position...it's gonna be a busy day."

Cortana:"The Covenant placed their tanks to defend the entrance to the tunnel."

(Type 3)

Marine:"Dang, they got armor support! Watch out for those tanks!"

Cortana:"The Covenant placed their tanks to defend the entrance to the tunnel."

(When you've destroyed the first Covenant tank.)

Marine 1:"Looks like that armor wasn't so tough after all! Let's mop up the rest of 'em!"

(When you reach the large interior cavern and engage the Covenant inside.)

Marine 2:"More Covenant sighted!"

Marine 3:"Man, these guys are like cockroaches!"

(As you reach the long rock tunnel leading up from the cave system back to the surface.)

Part 02: Rolling Thunder

(As you clear the area containing the fourth Wraith of the level.)

Sergeant: "You monkeys almost look like golden boys!"

Marine: "Damn straight!"

(As you come across two Hunters chasing after a squad of Marines, where the path switches back and goes down to a frozen river leading to the cave to the last area of the second chasm.)

Cortana: "I thought the Covenant had eliminated all the Marine forces in this area."

(As a Covenant dropship appears from behind the cliffs and drops in on the ridge you just descended from.)

Marine 1: "Anybody else hear that? Aw, man...Covenant dropship inbound, take cover!"

Marine 2: "The Covenant are dropping in behind us! We're trapped!"

(After you kill the dropship's troops)

Sergeant:(shoots dead enemy) "You're almost a man.

(As you near the switchbacks leading up to final area of the second chasm.)

Marine 3: "Whoa, Sir! The Covenant are dug up in those rocks! They've got us pinned down here!"

Cortana: {to Master Chief} "We need to get up this ridge." (O.S.) "Marines, hold your positions. We'll handle those guns." (to Master Chief) "Master Chief, we should scale the ridge and get below those stationary guns."

Marine 3: "I'm in no hurry for a heroic charge on those guns, Cortana. Holding position."

(As you reach the door leading into the cliff face.)

Cortana: "Cortana to Fire Team Zulu. I've sent a distress signal tagged with your current position. Hold your position and await evac. The Master Chief and I are going to continue on ahead."

Sergeant or Marine 3: "That's affirmative! Fire Team Zulu out!"

(As you clear the final area before the third chasm.)

Cortana: "Resistance appears to be increasing. We must be close to the Control Center."

(As you reach the door to the third chasm.)

Part 03: If I Had a Super Weapon...

Cortana: "Analyzing. This must be the Control Room. Subtle. The entrance to the Control Room is at the top of that pyramid structure. Bring me up there and I should be able to get us inside."

(As you open the door to the last leg of hallway leading to the Control Center.)

Cortana: "Scanning. Covenant forces in the vicinity have been eliminated. Let's move on to Halo's Control Room."

(As you open the door for the final cinematic.)

Cortana: "This is it. Halo's Control Center."

(The Master Chief walks through the door and to a control panel at the center of a circular glass walkway projecting into the middle of a massive open chamber. A holographic map of Halo surrounds a smaller holographic map of the system, which shows Basis and Threshold, and Halo itself between them.)

Cortana: "That terminal, try there."

(The Master Chief unplugs Cortana's chip from his helmet and places Cortana's chip in it. A moment later, she appears above the display. Data streams out from her in all directions. Her eyes are now red.)

Master Chief: "You all right?"

Cortana: "Never been better...you can't imagine the wealth of information. Knowledge...so much...so fast. It's glorious!"

Master Chief: "So...what sort of weapon is it?"

Cortana: "What are you talking about?"

Master Chief: "Let's stay focused. Halo...how do we use it against the Covenant?"

Cortana: "This ring isn't a cudgel you barbarian, it's something else...something much more important. The Covenant were right...this ring...it's Forerunner. Give me a second to access...yes, the Forerunner built this place, what they called a "fortress world," in order to...no, that can't be. Oh, those Covenant fools...they must have known, there must have been signs!"

Master Chief: "Slow down. You're losing me."

Cortana: "The Covenant found something, buried in this ring, something horrible, and now...they're afraid."

Master Chief: "Something buried? Where?"

Cortana: (looks horrified) "The Captain, we've got to stop the Captain!"

Master Chief: "Keyes? What do we-"

Cortana: "The weapons caché he's looking for. It's not really- We can't let him get inside!"

Master Chief: "I don't understand."

Cortana: "There's no time. Get out of here, find Keyes, stop him! Before it's too late!"

(The Master Chief turns and runs from the Control Room.)

General Walkthrough
Now you completed the easy part of the game, we can now move on to the longest part of the game. In the begining of the level, Foehammer will drop you off by the platform to the entrance of the control room, you will see Grunts running into the pressure doors to call upon their big brothers. Now you have two options. 1) Board the Shade Turret and gun everything down. 2) Wait for the door to reopoen and chuck a grenade over the oncoming crowds. The first option is a little bit risky, because if you're playing on higher difficulties, the Grunts will always get on the turrets before you can even get close. The second option is an immediate tactic which saves a lot of time, although the Elites may survive the blast. Swap a Plasma Pistol for the Assault Rifle for your next encounter. Venture into the short passage, the next room is litter with Grunts, but before that, you will have to take out the Elite. Use a charge shot to disable the Elites shield an gun him down with a pistol headshot. Fairly easy, but the minor elite may have spotted you, and he will began throwing ridiculous amount of plasma at you, lob a grenade at him to disperse the oncoming hord of Grunts. Journey your way across the room, BUT DON'T get near the doors, because you will be put down by a hail of plasma by Jackals and Grunts. Lob another grenade (plasma or frag grenades, it doesn't really matter) at them, and proceed onto the bridge. The Bridge is one of the toughest part in the level, with luck, you will loose one or two health bars; If you're the ones who always get pwned in Halo, you might loose all your health. Melee the Grunts with ease, do it swiftly, because they will wake up later on (thanks to Forhammers Pelican). Swap the Needler over the dead bodies. Again you now have two options. 1) Walk down the second level and blast the Major Elite or 2) continue your way across the bridge. The first tactic would be slow, but guarantee a safer route throughout your journey. The second tactic is quick, but will easily lead you into a situation where you find Grunts and Jackals surrounding you. All in all, you should succeed clearing your path with only pistol shots. Now I'll tell you what the needler is for. Once you are at the ned of the bridge, a Gold Elite with a Plasma Sword will come running at you. These are absoulute monsters, with grunts on their tails. Back away and fire rapidly at the Elite, stop and you're a dead man. There is an easier way though, throw a grenade to soften up the crowd, and take on the Zealot. Anyway, after a lot of raping and killing, walk into the next room. This room is fairly easy to complete, with a few Stealth Elites and Grunts, take them out with pistol shots and swap the Assault Rifle and health pack lying on the floor. Take them down to the basement. Now at the basement, you will encounter some sleeping grunts, melee them with ease, and proceed. You will soon find an Elite wandering aimlessly back and forth, melee him in the back or just chuck a grenade at him casually, this will certainly wake everyone up, even if you did the job stealthly, because someone on the other side will probably see you. Gun everyone down nice and clean and proceed into the snowy grounds. The snowy playground is quite a nasty place with Shade Turrets, far ahead, you will see Fire Team Zulu fighting with Jackals and an Elite. The Elite will start running towards the Ghosts parked underneath a small cliff top with a shade turret on it. Use your pistol to gun down the Grunt by your side and the Grunt on the cliff top, and proceed to the Elites. Beware of the Wraith's fire though, they're dead accurate at overturning vehicles. After you put down the Elite, Swap the Sniper Rifle or the Rocket launcher (Any one of them wouldn't matter, you'll probably run out of ammo before you know it, you can swap the two weapons, which isn't recommended). And get onto the Warthog, drive it to the sahdy areas to pick up the Marines (in order to dodge the Wraith). Dash Forward, you don't need to wait for the gunner (if you have one) to put down the aliens. You will eventually run into a crashed Pelican and meet the only Scorpion that's parked with Marines. Board the Scorpion and proceed. Again you have two choices (1)Take the route on your left or 2) Kill the Ghosts on your right and proceed through the tunnel. Both routes lead to the next area, but the first option would lead you into a state where you will be surrounded by Ghosts and Elites. The second option however, would lead you into a confrontion with a Wraith Tank. Anyway, clear the area and you will see a way down to your next destination. You can choose to eliminate the Wraith tank on top of the hills, but careful, a Banshee will come and fire plasma at you. Just keep your head down and go into the tunnel.

Walkthrough (On Legendary)
-	Ok...after you finished Silent Cartographer, you'll have a cutscene. After you get off, immediately chuck two grenades at the doors, as two Elites will come charging through, one a Major and the other a Minor. The grenades should extremely weaken the Major so use around half a clip in a single burst to take it out before its shields can recharge. If you timed the grenades right, the Minor should be dead. If you receive a checkpoint too late after the doors have already began opening, you might want to restart; this part is easily the hardest section in the whole level. After the door closes and the Elites have been dealt with, get into the Shade and simply hold down the fire button at the door. Grunts will fall at your onslaught without any resistance. Take heed-be careful not too let a stray Grunt escape for two reasons. First, it will distract your fire, allowing other Grunts to surround you. More importantly, it will sticky you, given the opportunity. By now, after clearing that part, you should have lost about one or two health bars. Proceed through the corridor and clear out the next room(s) by use of surprise/firepower. A hint to ponder: always kill silently until seen-the Major Elites can be extremely resilient, taking even a direct rocket in Legendary. Hey though, you wanted it! You might want to keep the Pistol, as it will help kill Grunts easily, and you will want it on the bridge. Ok, once you arrive at the bridge, you should quietly melee the Grunts to death. Hurry! You will want to kill the Major Elite on the second level of the bridge. Even if no-one sees you, Fire Team Zulu will arrive and wake everyone up. Try to kill the Major Elite, then man the Shade (preferably the one on the left-you get a better angle) and gun the Banshee down. Alternatively, you could use the Assault Rifle to destroy it. By now, you should also face the Jackals. Either use the Pistol that I told you to keep, or get a plasma pistol and repeatedly overcharge it into the Jackals, depleting their shields. Do not charge in-three seconds is all it takes to kill you by a group of Jackals. After you clear the bridge (it might take a long while-don't get frustrate!), the door should open and a group of Grunts, Jackals, and a Zealot should charge in. Halt! You can do this part of the level two ways, both of which will let you get past. First, simply spam the plasma grenade/fragmentation grenades at the entrance. All the enemies should be eliminated in no time. Alternatively, you could kill the Jackals / Grunts with your Assault Rifle, and then challenge yourself by killing the Zealot with only the Assault Rifle. This is often considered a difficult task, as previous experience from the Truth and Reconciliation has shown. This time, you do not have the overpowered Sniper Rifle, complicating your task. Simply dodge/jump (and time those!) and you should emerge victorious. You could take advantage of its AI by simply going far enough (It won't notice you or move). Simply go through the corridor, and you're in the next room! Take out the enemies (Grunts and Jackals) either through stealth or power-it doesn't matter. Then, you will see a Zealot with a plasma rifle. These are one of the hardest enemies in the game. Quickly take it out with a combination of the Assault Rifle and grenades (Plasma Pistols also work in place of the grenades-just use the overcharge to bring down its shield). The rest of the room, which consists of one or two Elites, should be dealt with easily enough. Proceed to the next room after reloading and stocking up on weapons. After fighting through a couple more rooms filled with Covenant, you should emerge onto the outside. First, you should be able to take the Grunt in the Shade with little problem, as he does not know you're there. Then, you can do one of two things. 1) You can gun down the Ghost from your Shade. However, this causes the possibility that you will get hit by the Wraith which is bombarding Fire Team Zulu, or your marines will all die before you arrive at their position. You do want a marine gunner to help take out the Wraith. 2) Alternatively, you could run towards the marines' position and, with cover from the trees, avoid the Wraith while dealing with the Ghost and infantry. This will probably result in a lot of health normally, so get in the gunner seat of the Warthog and gun the Ghost down. 3) Simply grab the rocket and fire at the Wraith, Ghost, and infantry to simply clear the area. You may want to conserve the Rocket Launcher for later, however. In my opinion, you should do a combination of the above. If you adore the sniper, go ahead and grab it. (While you're at it, snipe the Shade turrent on top of the massive rock-it is sort of hard to reach otherwise.) Get a Gunner and Passenger for your Warthog and roll on! A hint on taking down the Wraith: be careful of the ice. Once you're on the ice, you will stay in that direction and make you skid, making you an easy target. Remain on the ice, circle the Wraith, and the gunner will destroy the Wraith with ease.

Trivia

 * In the circular rooms you may hear a roaring sound. Deceptively similar sounds may be heard in Planar Sphere in Baldur's Gate II: The Shadows of Amn. It may be heard in the level Two Betrayals as well as here.
 * When you're passing the bridge driving a Scorpion you can hear the sound of cracking glass, despite the bridge windowpanes are not being broken.
 * If you break the windowpanes in the circular rooms, they will be in one piece again in the level Two Betrayals.
 * There are two weapon caches in this level. The first can be found if you go right after you enter the room with the two bridges, and the other is if you drop into the area where the spire leading up to the control room goes into the ground.
 * At the beginning of the level, when Foehammer drops you off the Pelican, when your HUD comes wait for it to say "Press X to enter Pelican" and press X. Then you can ride the Pelican off the map, and eventually, the Pelican will crash and you will die.
 * All the vehicles in Halo: Combat Evolved are available on this level.
 * This level has the highest number of Marines you will get to support you at the same time. It is possible to save 12 marines on this level with a mixture of Assault Rifles, Plasma Rifles and Sniper Rifles with one Marine wielding a Needler.
 * In this level Marines may enter and use the ghosts situated around the map on occasion.
 * If you send the Elite Zealot off the bridge as he dodges a grenade, you will see his body when you get to Fire Team Zulu's LZ.
 * This is the only level in which Sergeant Johnson and Sergeant Stacker are present at the exact same time. However, Stacker will not have his usual voice actor unless he is obtained by a glitch.
 * There is a Marine that is part of Fireteam Zulu that has a Needler. He and Keyes are the only known Marine AI's in Halo: Combat Evolved to be armed with one. There are also several Marines with Plasma Rifles, and both Sergeants have sniper rifles that they are surprisingly good with on lower difficulty levels.
 * It is possible to climb the narrow spire ascending the front of the pyramid. This is especially useful if you have a sniper rifle, as the headshot opportunities are numerous. It is interesting to note that the Covenant will not return fire when shot at, and that any sleeping Grunts will not awake while the player is on the spire.
 * In Halo 3, the mission start point for the final mission, "Halo" is named "Assault on the Control Room".
 * If you use one of the tricks to get to the valley floor early, you can find Sergeant Stacker among the Marines, the crashed Pelican, and the Scorpion tank as well as the Ghosts. Also only two of the Marines will hop in your Warthog, and they will not get out of it when you jump out, like they normally do.
 * If you manage to jump off the first bridge without going through the tunnel and live, you are able to go through the whole level without the Covenant attacking you, Although, eventually you will come upon a locked door and will need to restart the level or backtrack using the banshee found at the end of the last open area prior to the final open area to fully complete it. The banshee is necessary because you need a way back to the bridge. It is possible to take the banshee and land on top of the bridge with enough momentum to throw the banshee off causing it to be waiting for you once you have taken the long interior route down.
 * At the part when you get the Banshee, if you fly upwards at a 90 degree angle and fire either your plasma cannons or fuel rod cannon, they will go at another 90 degree angle behind you.
 * At the part where you emerge onto a bridge that overlooks the control room, if you're fast enough, you can hijack one of the two Banshees that are parked. If you do this, you can simply fly over the pyramid and skip fighting your way up. The best way is to get a Sniper Rifle and snipe the two elites that can get to the Banshee before you. Also, if you chose this method, you do not have to fight the two Hunters at the top of the Control Room spire (or anything else) near the elevated platform. The two at the bottom may or may not load. There will still be a few Elites, including a Zealot, behind the first door to the control room.
 * If you lure a piloted Banshee into the Control room, the cutscene then shows the Banshee soon splattering Master Chief but the dialog continues the same, as if Master Chief were alive.
 * If you were able to grab a Banshee on the bridge overlooking the control room, and use it to defeat the enemies past the first door/and or just fly it into the hallways, it shows in the ending cutscene behind Master Chief.
 * This level has the most Lekgolo (Hunters), with 12 in the level (which varies from difficulty settings).
 * The song Siege of Madrigal can be found at the end of this level. It can be found by flying a Banshee on the second bracket above the control room. Land the Banshee on the bracket and walk to the right until you reach the edge. Wait a few seconds and the song will start playing. It can also be found at the beginning if you fly a Banshee down the big shaft and stand on the right spot on the ledges.
 * The Two Dead Grunts easter egg is found of this level however it may be exclusive to the PC version of the game.
 * This is the only level with a drivable Scorpion tank in the Halo: Combat Evolved Campaign.
 * This level is remade and shortened in Halo 3 but you cannot climb up the Control Room central spine in the Halo 3 version.
 * The control room is shaped as the Marathon symbol if you look from plan view.
 * The first chapter in this level is "I Would Have Been Your Daddy". IWHBYD is a quote Sgt. Johnson says in Halo: Combat Evolved and is the name of one of the skulls in Halo 2 and Halo 3.
 * It is possible to get an Early Banshee before the bridge. Through this cheat, if you fly it high enough past certain points of the level, the enemies won't respawn for the rest of the level leaving empty vehicles and thus can be a good lifesaver on high difficulties. However bodies and ammo won't spawn either.
 * At the last part of the level, if you use a Ghost and time it correctly, you can have it ram you through the first door of the control room and the enemies there will not respond to anything the player does (killing one of them will not alert the others, they will not notice a plasma grenade stuck to their head, etc.). This can also be done with a Banshee although a bit more difficult.
 * No less than three hidden active camos can be discovered in this level. First, in the corridor filled with Stealth Elites, after you have killed all the Elites, go towards the end and look behind you. There, just in front of the second supporting structure to your right, there will be an active camouflage. This usually is only found if you already know of its location or stumbled across it by accident. If you just charge and avoid the fight with the Elites (not advisable as they will kill you), you will definitely miss it. In addition, the second active camo is found after you have come out of the enormous cave and defeated the Covenant reinforcements. There, there should be a tall building to your right, where more Covenant will come pouring out (Elites, Jackals, and Grunts). You can either kill all of them but probably lose a health, or you can get out and grenade-spam the entrance, as they will come charging out. After going into the structure, kill the two active camo Elites and snag your prize behind the pillar. Warning! If you take too long, two Elites will fire upon you from yet another entrance (there are three entrances to that structure).
 * If you use the Early Banshee glitch or modify the map to get a Banshee you can fly into the 1st and 3rd phase pulse generators which you have to destroy in Two Betrayals.
 * If you use the first active camo mentioned above, you will have just enough time to run continuously through the upcoming circular room, then out to the outdoor bit, and get the banshee. Wait one or two seconds later, and the elite would have got in the banshee, so be quick. It's good to kill the hunters in the room and the grunts/jackals in the hallway, then go back for the camo, otherwise you might waste time and it'll run out.
 * On the same structure, after going up the ramp tilted upwards and killing the two Elites, you will have a good sniping shot. From here, you can easily take out the Wraith with your rocket.
 * If you go out the only other "entrance", you will be in a place where you will arrive later on the Scorpion. It is advisable to use your active camouflage first here, as there are more enemies here, patrolling. Watch out for the Shade: it is hard to kill from a bad angle. After killing the enemies beforehand, grab your health pack (if needed) and some extra ammo.
 * This is one of the only levels in which a Zealot wields a plasma rifle rather than an Energy Sword.
 * If you use the trick to get the "Early" Banshee, and you flew very high, and you don't face any Covenant near or around the control room, and you try to proceed the normal way down to the bottom of the control room spire(through the other door on the snow bridge), the last door will be locked(lit in red).
 * The driver of the fourth Wraith can be killed before he enters the vehicle, although you still cannot drive the Wraith. At Rolling Thunder, get one of the Ghosts and drive all the way to the area with the Wraith while ignoring the enemies. An Elite can be seen making a run for the Wraith. You can use the guns on the Ghost or snipe him from a distance. A similar trick can be done on Two Betrayals.
 * This level holds the record for most Hunters appearances in the entire trilogy with a total of 12 Hunters (depending on difficulty).
 * If you spare some Grunts and Elites in the tunnel where you get the Scorpian, and you come back after getting to the big room with the Shades, the Grunts will be sleeping and the Elite will run to the crashed Pelican and get stuck on the top and keep on running into the wall.