Part 34

Sneak-shoot surviving marines, preferably with the pistol to conserve .357 ammo.

Ensure all enemies are dead, then collect any available armor batteries and weapons from the marines.

Return to your security guard and then proceed to the computer room.

Move through the winding hallway and sneak-shoot the marine at the left end with the .357.

Proceed down the hallway to a door on the left. (Note: A shortcut by activating the panel from the outside is not recommended as it skips the gauss gun.)

Go through the door, shut off the surgical unit using the control panel to the left of the walkway.

Get a scientist from the back room to follow you and retrace your steps to the lobby. Keep talking to the scientist to ensure they follow.

Head to the room with several crates. Break all crates except the one with a tripmine aimed at it. Collect bullet clips and use the first aid station.

Return to the hallway path split and go the other way to find headcrab cages.

Lure the headcrabs out by running in front of the cages, then move to a safe location and use your pistol to help your guard shoot them. Ensure all headcrabs are eliminated.

Go past the cages to a set of doors leading back to the lobby. Check the side hallway for a marine and eliminate them with the pistol if present. Use the lobby's HEV station for armor if needed.

Return to the headcrab cage area and go up the stairs between the cages to reach section c2a4f.

In section c2a4f, move near the top of the second set of stairs and wait for marines fighting bullsquids to stop.

Peek around the corner with the crossbow in zoom mode. If a bullsquid is near a large crate, shoot the crate with the pistol to let the squid attack the marine.

Shoot any visible marine survivors in the head with the crossbow.

Move forward to an open doorway on the right. Be prepared for a potential bullsquid in the room beyond and sneak-shoot it with the pistol.

Continue down the main hall, watching for marines at the other end.

Check the room on the right near the end of the main hall for marines and break boxes outside for ammo.

In the marines' room, pick up ammo boxes and use the first aid station if needed. Press the big red button on a panel to start a laser.

Go down a side corridor to a room with houndeyes. Quickly kill them with the assault rifle or shotgun, then press the room's big red button to activate its laser.

Return to the main hallway and find another branch to the right with explosive crates. Move into this hall until you hear voices, then wait for the guard with the experimental weapon to overcharge it.

Go down the side hall and into the room beyond. Pick up the experimental gauss gun (tau cannon) from the floor.

Find and use this room's laser-starting button.

Return to the main hallway and go back to the room where you sneak-shot a bullsquid earlier. Collect armor batteries if needed, then press that room's laser-starting button.

Go back to the primary laser room. Push the movable crate to obstruct the laser shield when it lowers.

Press the big yellow button on the nearby console to fire the laser, creating a hole in the wall.

After the laser stops, crouch-walk slowly through the hole to drop onto a small metal ridge against the wall.

Walk along the ridge to the corner, drop onto a square joint on a vertical pipe, then drop to the next small metal ridge, and finally to a curved section of pipe to reach section c2a4e.