After out of the airlock go the room 1B and pick up the security armour and enter through the next door into an office. Use the health station and pick up the PDA. Press the panel to activate the primary pump systems. I cool scene starts here and after two imps will come through the window in front of you. Go through the widow and kill the two imps that appear and jump on the pump and ride it up to the catwalk. When up there go through the northern door. Be ready again for a jumping imp scary gag. And another one follows that and also one teleports behind you on the catwalk. When you go to the next hall two lost souls will fly at you. If you have good aim and don't want to waste ammo use your pistol for these little bastards. Go through the north-eastern door to get another mission. The cabinet next to the Monorail access door has the combination: 483. There is armour and ammo in it. Walk down the hall north.

When you go in the gas pump room there is an imp to the left. Go to the north part of the room. Betruger will try to intimidate you. Go back to the last hallway and kill the revenant there. Then two lost souls appear. After you kill them use the health station in the northern part of the room. Now go through the north door and you'll get to a hall. Kill the zombie to your left and the imp to the right. Pick up the shells and cells of the center shelf. In the northern area is some security armour. Now go through the next door to the maintenance room. Kill the imp that drops from the ceiling. When you walk further a revenant will come through the door behind you. A door in the middle of the hallway will open with and imp coming out. Once you kill it continue down the hallway and get the rockets and med kit. Then go back through the door the imp came out of. Go east and kill the fat zombie that pops out of the shadows. Some shells are near him. When you get to a T intersection kill the fat zombie and imp to the right as well as a revenant and a zombie to your left. Turn so your walking to where the revenant came from. After your next objective come up go back in the opposite direction to clean up the waste. When you get to an imp blow up the barrels near him and go through the next door.

Two lost souls will appears so kill them then go south to a door where a revenant and an imp come out. Pick up the supplies and go through the door. When you approach the center of the room two imps will spawn in front and back of you. Shells are near the imp behind you. When both are dead go through the next door. To the left of the entrance kill the zombie and picl up the stuff on the shelf. There is also a health station in that room. Use the panel to vent the hazardous gas. When you do so three imps will spawn in the northern part of the hallway and a zombie in the southern part. Its good to use a shotgun or a plasma gun on a group of imps like that. Now backtrack to the locked door, which is now unlocked, and kill the revenant and the zombie on the way. When you get to the door an imp and a revenant will attack. When they are dead proceed to the hazardous material room. When you enter another revenant enters on the other side. Shoot the barrels to kill him. Pick up the ammo belt and shells and go through the next door.

When you go down the hallway eight cherubs will attack. kill them before they get to close because when this many attack you at once its hard to aim. Proceed down the hallway and use the health station if you need it. Before leaving get the armour and ammo on the shelf. Kill the imp on the other side and go up the stairs. An imp will come through the last door as well as another one above you on the stairs. When dead pick up clips and shells on shelf and go up the rest of the stairs. At the top you will need to kill yet another revenant. Now go through the door.

Touch the control panel to activate the lift. Ride it to the bottom and kill the two cherubs around the corner. Go through the door to the west and kill the waiting cherub. Pick up the ammo and continue in the alcove pick up the clip and shells. Then continue through the hall. When you enter you past the point of no return. You will meet the most powerful enemy in the game (that isn't a boss). It's called a Mancubus. It has A LOT of health and packing two rocket launchers. If you are good with grenades keep strafing and throwing them at it. As long as a wall isn’t behind you and your strafing you are invincible to these fat things. Just make sure you never stop strafing. Pick up the items scattered all over just in case. Two more will come after the first one is dead. Once they all are kill the three cherubs that attack and go up the catwalk and kill three more cherubs. Then ride the elevator up.

Pick up the health and ammo to the right and don’t waste time because the air hurts you. Go down the hallway and quickly use all three panels to stop the gas and then kill the revenant at the end of the room. Go up the stairs and find a PDA and a med kit. Keep going until you reach the Monorail access door and then go through to continue to Monorail.