Alpha Labs - Sector 3: Union Aerospace Science Division


Doom 3 maps
Alpha Labs - Sector 3: Union Aerospace Science Division
Map name: game/alphalabs3

Alpha Labs - Sector 3: Union Aerospace Science Division is the seventh level of Doom 3. This level contains a well-hidden plasma gun and an optional chain gun.


The marine continues advancing through Alpha Labs. In this sector the marine needs to go through an area locked by maintenance key 4, which is located in a room filled with toxic gasses emitting from some of the barrels. The marine needs to use the manipulator to pick those barrels up and throw them away into the incinerator, and after doing so the marine is able to pick up the key and go through the locked door. The rest of the sector is a straight forward walk through a series of rooms, although the marine can enter an optional passage that contains a chaingun and armor - he will be ambushed upon picking them up. In the last room after the marine deals with multiple pinky demons, a strange unseen force throws items including a mop bucket around, breaking the glass window and allowing the marine to proceed to the exit.


Air Lock
AL2 Main Engineeering Junction
Hazardous Waste Disposal
Hazardous Materials Lift
Coolant Monitoring
Boiler Room
Boiler Room Monitoring
Storage and EnPro Facility Access
Heavy Water Runoff
EFR Staging Room 1B
Air Lock


Contaminated Chamber
Remove the barrels leaking toxic gasses in the chamber.
Alpha Labs Sector 4
Locate the entrance to Alpha Labs Sector 4.





The enemy count on Nightmare is the same as on Veteran. There are no changes in the enemy amount in the BFG Edition.

Enemy Recruit Marine Veteran
Zombie 7
Pistol Z-Sec 4 5
Shotgun Z-Sec 5 10
Machine gun Z-Sec 4 5
Imp 8 11
Demon 2 3
Maggot 7
Trite 19 24


The item count on Nightmare is the same as on Veteran, except the med kits are absent.

There is also one health station on the level with 100 health in reserve.

Starting inventory[edit]

If the player starts the level via a console command, they will start with these items:

Item Amount
Flashlight 1
Shotgun 1
Machine gun 1
Shells (small) 1
Shells (large) 1
Clip (small) 1
Clip (large) 1
Grenades 1

Locker codes[edit]

The code to all the cabinets is the same: 123, due to incompetence of the staff. For the sources of the codes, see Doom 3 locker codes.

  • Storage locker #047 - Ammunition. Contains: hand grenades, clip (large), clip (small).
  • Storage locker #048 - Ammunition. Contains: med kit (large), cells (small), bullets (large).
  • Storage locker #049 - Ammunition. Contains: ammo belt, shells (small), armor shard x5.


  • In Coolant Monitoring, jump on the pipes below the stairs to the Boiler Room and crawl to find a med kit and some clips.
  • There is a well hidden plasma gun on this level. To get it, the player needs to open a maintenance hatch using a control panel in Boiler Room Monitoring, then go to the previous room, enter the hatch to the left of the door, proceed through it, turn right, and push the cross-barred panel outward. The player then needs to jump on one of the pipes to the right, and the plasma gun will be lying on it near where the pipe connects to the wall (the player will need to crouch to get to it).
  • There are clips and armor shards if the player walks on top of the pipes back to the entrance to this room.


  • On the original Xbox version of the game, a large part of this level and a very small part of Alpha Labs - Sector 4 were merged into one level Alpha Labs - Sector 3.
  • If the player goes to the manipulator control room and stays there for two minutes without going out, a Z-Sec will appear behind the door and surprise attack the player.
  • It is possible to jam the incinerator crane against the wall with the window which allows viewing the toxic barrels. If done in just the right way, the crane will become unusable, and if the toxic barrels were not yet incinerated, a soft lock condition will occur, requiring the level to be restarted from the beginning.
  • There is a machine gun Z-Sec on this map that is not activated by any trigger, thus this enemy does not actually appear on the map.
  • Two shotgun Z-Secs will spawn when you kill the farthest imp on the right in boiler room monitoring, if you have not walked past the last L-shaped zombie alcove. If you walk past it and then exit the room, the Z-Secs will no longer spawn.


External links[edit]

  • Walkthrough video by WoopzillaWalkthrough (part 1; part 2) on YouTube. Veteran difficulty; part of a full game run.