You will start out in the Bay that you exited the last level in, walk through, and end up in a garage-like room with two trams. Go forward and to the tram to the left, as the right one is locked shut. Walk into it, and start the tram, and go for a little ride.

Once the ride is over, step out of the tram, and find that there are two dead humans near you, if you need souls, grab em. You will now receive a new objective: Shutdown the Phobos Labs Main Reactor. There are two doors to your left, both with signs above that say "Reactor Operations". Go through either door, as they both lead to the exact same place, once in the room, fight off the number of enemies inside, a mix of Vulgars, zombies, and Revenants. Then go up the small stair set and to the next room.

In here, there will be nothing of significance, take a left and through the door to the next room. You will come right into a huge room with what looks like the reactor you were told to shut down. Continue down your path to the right, fight off the 2 Cacodemons and Forgotten, and hop on the lift and activate it. Once you are lowered, head to the path to your left, as more enemies will spawn, once again being Cacodemons and Forgottens. You will come to a second lift, hop on and activate it. Head to your left, come to a large door, and walk into the next room. Walk forward and down the ladder, kill a zombie, walk a little bit to your right, and down the second ladder. To your right and behind you will be a third ladder, head down that one as well. There will be a PDA and keycard sitting on the desk. Pick those up, turn around, and activate the lift, and ascend. Once you are up, head down the path and through the big door you entered this area in. A Vulgar will spawn right in front of the door, kill him, and retrace your steps up the lift, killing another vulgar right in front of it. Raise the lift, head right, and up the second lift, with alternating Cacodemons and Forgottens spawning along the way, once you are on the top level, head on to the right and to the door, requiring a keycard you collected on the desk before. Once in this room, go to the computer in front of you, and Initiate the reactor shutdown, head to the left and enter the locker code '492'. Now you will receive a new objective: 'Shutdown Phobos Labs Life Support Systems'. Head back to the large reactor room, and activate the bridge on the access panel, head down the bridge and through the door.

You should now see a dead marine and pipes in front of you, to your left 3 Z-Secs will attack you, continue down the path, and find that there is a lift, hop on and activate it. As you descend, it may be a smart move to bring out your artifact, once the lift has stopped, many Revenants will spawn, along with one Pinky-Demon. Once they are all dead, head to the door to the left of the lift, You'll find yourself in a room with a series of pathways, go left, and now a Security Drone will activate to assist you. Simply follow the bot, and help him destroy the vast number of Vulgars and Wraiths that continue to spawn. Once at the end of the path, the security drone will deactivate, with an elevator right in front of you. Walk inside, and on the access panel select 'Airlock'. Once you have reached the floor, there will be a plasma gun and cells in front of you, and an airlock to your left. Collect the ammo, and into the airlock. Now once you are outside, take a left down some stairs, and collect an oxygen tank in front of you, turn around and head down the ladder, walk forward to the second ladder, down that ladder and to the next airlock. Once it opens, there will be a Z-Sec right in front of you, take him out, along with another Z-Sec to your left, with 2 Vulgars that will spawn. Kill them and head down the stairs, and into the elevator, once inside, select on the access panel 'Cargo Tunnel'. You will find yourself in a very large hallway-like area, that is probably used for vehicles, take a left, and through the door ahead of you, you will now be in a large area with multiple barrels and dead people strewn about. To your left, there will be an access panel, activate 'open window seal', Now you have yourself in a heap of trouble.

Keep going down the path, killing the multiple Hell-Knights and Revenants spawning, Now is one of those times where you should use the artifact frequently. Once you have gotten to the end of the path, you will see an elevator on fire, and a large door in front of you, go through the door, and right away you will find that a pinky demon is RIGHT THERE! I don�t know about you but that made me jump! Kill him and take a left, then a right, continue down the path, Head up a flight of stairs, and Kill the Revenant coming down a flight of stairs in front of you. Head up the stairs the Revenant was on, and go down the path, killing 2 Z-Secs on your way. Once at the end, you will find a ladder to your left, a Vulgar will spawn, kill it and go up the ladder.

In this room, head straight forward, ignoring the left turn for now. Go inside the office, finding an access panel. Activate 'Initiate Shutdown', go back out of the office, and take a right, keep walking straight down the hall, coming to a door that reads 'skywalk' on it. Go through the door and into the skywalk. Walk Across the skywalk and find a room, with a bay, on the access panel to the right, activate 'open bay door' Go inside and exit to Phobos Labs: Sector 1.