Part 10

From a wall niche, move carefully along beams to enter another vent shaft. Bash its grate, then shoot the headcrab in the room beyond.

Crouch-hop over beams to a weak ceiling tile that drops you into a secret ammo room. Take supplies, then exit and go left to return to the security guard's location.

Go down the large ramp near the guard and turn right. Destroy the middle crate with your pistol from a safe distance to reveal and safely shoot the bullsquid behind the crates.

Loot the area for grenades and shells. Push two barrels up to the yellow floor line to mostly block the path.

Move past the yellow line to trigger two vorts to teleport in. Quickly get behind the barrels and shoot the vorts over them.

Go back up the ramp and have the security guard follow you. Proceed past the secret supply room's door into a large cafeteria.

Toss a grenade at the zombie near the tables. Help your security guard kill it and any headcrabs that fall into the room.

At the back of the cafeteria, bash boards off a doorway with the crowbar and go down the hallway until section c1a2c loads.

Optional Skip: Lead your guard down the short hallway to the left of the cafeteria to a locked door. Nudge him until he opens it, bypassing section c1a2c. Note that the guard and zombie in the next area will be missing.

Around the corner is a room with two zombies. Leave your guard behind before entering, toss a grenade, and finish survivors with the shotgun. Retrieve your guard.

Use the large lever left of the big door near the zombie area. Run through before the door closes, or use the lever from the right side to reopen it if your guard doesn't make it.

In the meat locker, go through the large open doors, turn right. Let a headcrab see you, then retreat so your guard shoots it. Bash past hanging meat.

Shoot the headcrab on the floor and the one on the high shelf, or let your guard assist.

In the next large room with three hanging pieces of meat, shoot the headcrab and the bullsquid hiding behind crates. Aim for the bullsquid's leg until it dies.

Find the big red-lit switch on the wall and use it. Move down the hallway and turn right into the back rooms.

A scientist will run, chased by a bullsquid. Help your guard take down the squid, then whack the scientist for ammo. Loot bullets and grenades from the room the squid started in.

Return to the starting room and climb the short ladder to a shelf. Break the vent grating at the other end and jump-crouch into the vent shaft.

Break out of the vent shaft and follow the shelves to a moving platform. Board it when it passes, breaking its crates for armor batteries. Exit at the vent opening across from where you boarded.

With your flashlight on, move down the vent shaft to a spot where it drops to a lower cross-shaft. A headcrab will jump up; edge forward to sneak-shoot it, then drop down.