Dawn/Walkthrough

Walkthrough
Once you exit the cryo tube and retrieve Cortana, you should retrieve a pistol you can find on the floor, near the left of the room. Proceed through the level to the elevator. Open it, and enter the shaft. Hold up left stick to move upward, and when the chief glances to the side, jink the left stick in that direction. Procede upward while dodging debris to get up the shaft. At the top, you are engaged by an Elite with an energy sword. Follow the button commands (in my experience it is RB but it may also be whatever you use for melee) and hurl him down the elevator shaft. Continue until you are outside the observation deck. You will see an elite several yards directly ahead on a slightly raised platform at a console with his back to you. Charge him, get an assassination or beat down, and use your pistol or assault rifle to finish off the Grunts below you on either side of the room. Cortana will tell you to hit a button on the console that the Elite was fiddling with, but first, stock up on ammunition. There are several ammo crates in the room, mostly close below you. Fill up your pistol, stock up on grenades, and swap your Assault Rifle for a Plasma Pistol. After you've prepared yourself, hit the button on the console. Soon after, two phantoms will flank you and place two boarding craft on the windows. Frag the areas where the covenant jump out, kill the grunts with headshots, and EMP the Elites' shields with your PP before killing them with your magnum as well. After clearing the area, follow Cortana's waypoint to the elevator. (Ok, I'll to stop here for now. I'll continue soon if someone else doesn't do so. If you were planning on using this guide, sorry. It probably wouldn't be that good anyway ;)