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The first thing you see when Foehammer drops you off is a Grunt running into a door. Quickly run to the nearest gun turret and get in. As soon as the door opens, start blasting the Covenant that come out. There's an Elite in there as well, so watch yourself. If they get out of your range of fire, get out and finish them off with your Assault Rife or Pistol. After killing them all, grab any plasma weapons that you fancy (if you fancy them that is) and head for the door. Be careful, there are still some Grunts inside. Kill them when you run into them. Walk quickly along the hall way. When you get to the next door, be careful. There's an Elite outside. Take him down any way you want. As soon as he hits the floor, continue onward to the right. There are quite a few Jackals and some Grunts in here as well. Don't kill all of them (unless you are on a higher difficulty), you'll need your ammo later. Move around the place till you come to another door. Look on the ground in front of it. If it has a glowing arrow-like thing on pointing towards it, go in. If its pointing away from it, don't enter. This is the door you came from. When you find the right door, head in. Be careful of the Grunts in here. Continue onward once more. After several more twists and turns, you will come to another door. This will lead out to a bridge. Now comes the fun part. There are several Grunts asleep here, so melee them to death. If you screw up and wake them up, kill them normally. Continue carefully across the bridge, as there are more enemies here.