fully automated and personnel access is limited due to open machinery hazards.

Your guide to Alpha Labs Sector 4: Union Aerospace Science Division in Doom 3. Learn how to navigate the automated systems, deal with hazards, and face the Vagary.

Alright, so you've made it to Alpha Labs Sector 4, the Union Aerospace Science Division. This place is pretty wild – it's mostly automated, and they've really limited personnel access because of all the open machinery. Think of it as a giant, dangerous factory floor. You'll be navigating through either the EFR or a maintenance bridge to move forward. Keep an eye out for the "To Be or Not to Be" segment and that creepy "they took my baby" part. The big boss here is the Vagary, so be ready for that when you reach the end. When you start, there's a health station – definitely use it up, as there's a point of no return coming up soon. You'll run into Larry Kaczynski, who's in a bit of a bind. You can either put him out of his misery, which spawns a couple of Z-Secs, or save him. Saving him is the way to go if you want a PDA that'll be super useful later for a BFG9000, plus a video disk. After the reactor, get ready for some long-range fights with Z-Secs positioned up high. Then you'll deal with Trites, followed by more Z-Secs, and then some more Trites. Keep an eye out for a cache opening on your left; it's got goodies and a Z-Sec. You'll also find an Adrenaline boost there. After that, you'll see two doors. The left one leads to an empty corridor, but you'll hear some unsettling things – voices, a baby crying. If you stick around, you'll find some goodies. The second door opens into the massive EFR room. You have a choice here: activate one of the two options on the computer, or head down the ladder. Down there, you'll find a Medkit and two Imps – one right in front of you, and another behind. After that, follow the path to grab some Security Armor. More Imps will spawn one after another, so this is a great spot to use grenades. Once you clear them out, a container will open with ammo, including more grenades and plasma. From here, things split depending on your choice at the computer: ### Activate EFR Save your game often here, because there's a fair bit of jumping involved. Follow the path into a small room and take out three teleporting Maggots. Then, activate the computer to open the next door. Go through and take out the Z-Sec on the left. If you want to explore, the room to the left has some Z-Secs hiding behind shelves, plus two more Maggots and some Stimpacks and ammo. Outside this room, there's a pit with moving platforms. If you time your jump right when a platform appears on the left, you can hop onto a pipe and crawl through a narrow space to snag a Plasma Gun and some extra plasma cells. The platform will then take you to the EFT Magnetic Discharge room, where you'll need to make some more tricky jumps. Before you leave, grab all the health and items you can, as another platform ride awaits. This one leads to EFR Junction 6, which is a series of tight corridors with explosive barrels and Z-Secs. ### Activate Maintenance Bridge This path doesn't involve as much jumping, but be prepared for a lot more fighting. As soon as you choose this option, two Z-Secs will pop out from behind you. Keep moving, and you'll encounter two Imps and a swarm of Trites before reaching the next door. Behind that door, there's a Z-Sec and a pit. Take the only available door into the storage area. You'll find some Z-Secs hiding behind shelves, along with two Maggots, some Stimpacks, and ammo. After that, cross the bridge, grab the Security Armor, and take out the Imp that appears on the side. Climb the ladder and proceed through the shaft, dealing with Trites and two Maggots along the way, plus an Imp at the end. You'll then arrive at EFR Junction 3, a small platform with a Security Armor. Grabbing it opens up an optional path to a dark area where you can find a Plasma Gun and some cells. Be warned, though: taking it will spawn about half a dozen Imps in that tight space, and two Z-Secs at the exit. Crossing the bridge will lead you to the EFR Master Valve room.