Assault on the Control Room shortcut

Introduction
The Assault on the Control Room Shortcut requires very good timing, so it may take some practice before you can get it. First go on to the first bridge, and make sure you have a plasma grenade. Try not to wake up any Grunts, as they will be annoying and dangerous. Throw a plasma grenade on the ground, right next to a Shade. Right when the grenade explodes, quickly press X (E in Halo PC) to get in the Shade. If you're lucky, the shade will right itself and you will fall safely to the ground. By doing this, you can skip three quarters of the level. Another way that requires skill, practice, luck and co-op is to jump. This cannot be done on Halo PC. First, when you get to the bridge with the sleeping grunts, jump off next to the shade on the LEFT side (you wouldn't believe the amount of times I went off the wrong side) and you will fall on a thin ledge. Stay close to the wall to do this. If you accidentally woke up our grunty pals, the elites will shoot at you. Since you lose shields when you fall this is bad and you can die. Run down the ledge to the lowest part, then a little further. Have your partner commit suicide, then fall down. You must be close to the wall or this will not work. You will fall past a ledge, where your partner should respawn. You will respawn next to him. Run along the ledge, taking care not to fall as it is slippery. Run over to the part that is directly above the large rocks. Drop down onto them, and you will survive. Note there are no enemies, and all the usable vehicles that the enemy usually steals can be used. You cannot, however, finish the level as a door near the end will not open.

reply to note: The red door towards the end is after a set of two bridges, if you jump on top of the glass on the edges of these bridges you can jump the gap, and yes complete the level.

Performing the Shortcut
At the bottom is a snowy and empty world. Events that are going to happen haven't happened yet, because the things that trigger them haven't been done yet.

Another trick is when going out on the rocky bridge right by the pyramid, run out and steal a Banshee. You can then fly over to the pyramid and activate the door and use the Banshee to kill the Covenant forces inside. This can be difficult sometimes. But attempt to take out the Major Elite (nearest the Banshee) first, then take down the Minor Elite, preferably with the Sniper Rifle.

NOTE: Unless you're fast, the other Banshee will launch and try to kill you. So either kill them when they show up or just knock it off the bridge.