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ALPHA LABS - SECTOR 4 - "Alpha Labs Sector 4 seals and prepares shipments of processed hydrogen fuel for dropship distribution to UAC bases and subspace platforms. The system is fully automated and personnel access is limited due to open machinery hazards."

Alpha Labs - Sector 4: Union Aerospace Science Division is the eighth level of Doom 3. The final portion of the Alpha Labs, the player is approaching closer to Bravo Team, who just entered the adjacent Enpro Plant. This sector houses the delivery machinery which transports resources generated by previous sectors throughout the base. The player must therefore navigate through either the EFR or the bridge to proceed on. This level features the "To Be or Not to Be" segment, and the infamous "they took my baby" sequence. At the end of the level, the Vagary appears.


  • Air Lock
  • Reactor Ready Room
  • Reactor Control Room
  • Reactor Room Lift
  • Reactor Junction 1
  • Reactor Sub Station 1
  • Reactor Junction 2
  • Reactor Processing
  • Processing Junction 2
  • Processing Junction 1
  • EFR Staging
  • Maintenance 12 (Extend Service Bridge Only)
  • EFR Substation 1 (Activate EFR Only)
  • EFR Junction 1
  • EFR Storage PT 3
  • EFR Main Conveyer
  • EFR Magnetic Discharge Station (Activate EFR Only)
  • EFR Substation 2 (Extend Service Bridge Only)
  • EFR Remote Access Junction 1 (Extend Service Bridge Only)
  • EFR Remote Access Junction 2 (Extend Service Bridge Only)
  • EFR Substation 3 (Extend Service Bridge Only)
  • EFR Pressure Station (Extend Service Bridge Only)
  • EFR Master Valve (Extend Service Bridge Only)
  • EFR Junction 5 (Extend Service Bridge Only)
  • EFR Junction 6
  • EFR Junction 7
  • EFR Junction 8
  • EFR Junction 9
  • EFR Main Shipping Hub
  • Air Lock


At the beginning, you have an health station ; use it fully as there is soon a no-return point. You'll encounter Larry Kaczynzski, trapped in a device and asking for help. You can chose to kill him (which spawns 2 Z-Secs) or save him (you'll get a PDA who'll be useful far later to have a BFG9000, and a video disk).

After the reactor, the first long-ranges battles against Z-Secs on high spots occur. Then, there are Trites, then another 2 Z-Secs, then another Trites, then a cache opening on the left revealing goodies and a Z-Sec, and an Adrenaline boost. Then there are 2 doors. The left one leads to an empty corridor, where the famous "help me", "follow me Marine" and "they took my baby" words and baby's cry can be heard, which spawn goodies. The second door leads to the huge EFR room. You can activate one of the two options on the computer, or optionally go down the ladder. There is a Medkit and two Imps spawning down there : one in front of the Marine, the other in his back. Then, you can follow the semi-circular path leading to a Security Armor. Imps will spawn one after another here, it is a good occasion to use Grenades ; killing all Imps will open a container with ammos, including Grenades and plasma. The following parts of the level depends on what option you chose on the computer.

Activate EFR[]

Save often, because there is a lot of jumpings. Follow the path, enter the tiny room, kill the 3 teleporting Maggots, activate the computer to open the door further, cross this door and kill the Z-Sec on the left. If you want, you can clean the room on the left ; there are some Z-Secs hiding behind shelves, then 2 teleporting Maggots and 3 Stimpacks, along some ammunition. Outside this room, there is a pit, with moving platforms. If you jump when the platform spawns on the left, you can then jump on the pipe and crawl in the narrow space to collect a Plasma Gun and plasma cells (for a total of 100 Plasma rounds). The platform then transports you to EFT Magnetic Discharge room where you have to make dangerous jumps again. Before exiting, take all Health and items you can, as there is another platform ride. This one lead to EFR Junction 6, which consists into narrow corridors with explosive barrels and Z-Secs.

Activate Maintenance Bridge[]

This option does not require jumps, but implies lots of fightings. As soon as you chose the option, 2 Z-Secs spawns from behind. Following the path, there are 2 Imps and a lot of Trites, until the next door. There is a Z-Sec and a pit behind. Take the only door to enter the storage area. There are some Z-Secs hiding behind shelves, then 2 teleporting Maggots and 3 Stimpacks, along some ammunition. After this, cross the bridge, take the Security Armor and kill the Imp who appear on the side. Then climb the ladder, and proceed through the shaft, killing Trites and 2 Maggots on the way, and the Imp at the end. You then arrive in a the EFR Junction 3, a small platform with a Security Armor. Taking it open an optional new path, leading to a small dark area with a Plasma Gun and some cells ; taking it spawns half-dozen Imps in the tight area, and 2 Z-Secs at the exit. Crossing the bridge leads to the EFR Master Valve room with a Health Station and the "tools" locker. Path then leads to a big room with a huge load of Trites. After this, you arrive in EFR Junction 6, with Z-Secs, explosive barrels, narrow corridors, Medkits and a second Adrenaline booster.


The two paths leads here. From EFR Junction 6, the Marine can join EFR Junction 7 which is a small room with Z-Secs, then a corridor where he can sees Swann and Campbell, the later using is BFG9000 on Trites, then another tiny corridor with an hidden Imp, then the final room with an Health Station. Grab all you can, as once you cross the door on the right, you can't back. The cinematic introducing the Vagary is played, and the battle begins. To win, simply shoot the Vagary with Plasma Gun or Chaingun until she dies. There is Adrenaline in the room, but it is hard to understand what manner it can help you.


Video Disks[]



Monster Count
Vagary 1
Imp 21/21/23
Maggot 7/7/8
Trite 71
Machinegun Z-Sec 14
Pistol Z-Sec 4
Shotgun Z-Sec 9
Weapon Count
Shotgun 9
Machine Gun 3
Chaingun 1
Plasma gun 2
Ammunition Count
Pistol ammo (small) 2
Pistol ammo (large) 1
Shotgun shells (small) 4
Machine Gun ammo (small) 11
Machine Gun ammo (large) 8/8/7
Chaingun belt 6/6/5
Plasma cells (small) 4
Plasma cells (large) 4
Misc. Items Count
Adrenaline 4
Small medkit 6/6/4
Large medkit 14/14/8
Armor Shard 53/53/56
Security armor 11/11/9
Video Disk 1
  • For cells of the form x/y/z, x corresponds to Recruit difficulty, y to Marine, and z to Veteran/Nightmare.
  • Items that can only be acquired by using console commands are excluded.

Cabinet Codes[]

  • Storage Cabinet #064: Tools - 651



  • There are two dead shotgun Z-Secs by the door that leads to the fight with the Vagary, most likely killed by Campbell.