Alpha Labs - Sector 4: Union Aerospace Science Division

Alpha Labs - Sector 4: Union Aerospace Science Division is the eighth level of Doom 3. This sector 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.

The player must navigate either the EFR or extend the service bridges. The EFR activates various moving platforms throughout the level, while the service bridges provide a quick but dark crossing. At the end of the level the Vagary (first boss) appears.

The level also includes the infamous "they took my baby" sequence.

Summary
In order to reach EnPro Plant the marine must go through the final sector of Alpha Labs. In the beginning of the level the marine finds a scientist trapped in a reactor chamber and is given the option to open the chamber or activate it. If he chooses to open the chamber, the scientist opens the storage room full of supplies for the marine. If the marine chooses to activate the chamber, the scientist will be horribly murdered inside the chamber and the marine will be rewarded with nothing but an enemy ambush. Proceeding through the sector, the marine is informed by Sergeant Kelly that he'll have to make another choice: to get around the level the marine must either use the EFR system or extend the service bridges. The first way requires the marine to jump between multiple platforms and ride on conveyor platforms avoiding various machinery, but in this case the marine won't meet a strong enemy resistance. If the marine chooses to go the service bridge route, he won't have to do any platform jumping, but will have to fight more enemies along the way. In the end, the marine reaches a large chamber covered entirely in web and organic matter where the marine has to fight the game's first boss, vagary. The same chamber has the exit to EnPro Plant.

Objectives

 * Enpro Plant
 * Reach the Enpro Plant as quickly as possible.

Characters

 * L. Kaczynski
 * Sergeant Kelly
 * Elliot Swann
 * Jack Campbell

PDAs

 * Michael Abrams. Found in Reactor Substation 1.
 * Larry Kaczynski. Can be obtained by killing Larry Kaczynski.
 * Henry Nelson. Found in EFR Staging.

Video disks

 * Mach-2 Chain Gun Briefing: Found in Reactor Substation 1.

Enemies
Note: since there are two paths the player can choose in this level, it's impossible to kill all enemies in one playthrough. This table includes only enemies that can be fought and killed. The enemy count on Nightmare is the same as on Veteran.

Items
There are also four health stations on the level, with 100 health in reserve each, although only three of them are accessible at any one playthrough.

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

Locker codes
For the sources of the codes, see Doom 3 locker codes.
 * Storage locker #064 - Tools: 651. Contains: cells (large), clip (large), armor shards x3. This storage crate can be accessed only by using the service bridge route.

Secrets

 * There are two plasma guns hidden in this level, one for each path the player can take. If the player decides to use the EFR system, they can access the plasma gun at the very start of the conveyor sequence. The player has to jump on the platform right after it emerges, then quickly jump on the pipe above it, and the plasma gun and other supplies will be lying behind the pipe. However, if the player chooses to use service bridges, they can find one by finding a secret passage located in EFR Substation 3 room. In that room, there's an armor suit sitting near a wall that opens when getting close to it, opening the passage. A voice is heard saying "Over here". The plasma gun and other supplies are in a room at the end of this passage. One should be careful, as picking up the plasma gun here triggers an ambush.
 * In the room where the player needs to choose between raising the bridges or using EFR system, there a ladder that leads down to some supplies and an ambush. However, the player can jump over a nearby pipe and explore the rest of the area below, and eventually can find a lone armor suit sitting on the floor. Upon getting close it, it triggers a massive ambush, but upon fighting it, opens up a closet with even more supplies.
 * During the conveyor sequence (if the player chose to go using the EFR system), the player will need to get past a rotating device with long "arms" sticking out of it. The player can jump on it and get pushed by the "arms" behind said device to find some additional supplies. The player can return to the platform the same way.

Trivia

 * On the original Xbox version of the game, this level was merged with Alpha Labs - Sector 3 into one level titled Alpha Labs - Sector 3. It should be noted that only a very small part of this level was used in that version (specifically, the very end, where the marine fights Vagary).
 * At the beginning of the level before stepping out of the airlock, a pair blinking eyes can be seen behind a crate. When the player movies closer, the eyes hide behind the crate and disappear while a whispering sound can be heard.