Part 12

Upon entering the area, check near the teleport-in point for a first aid station and bullet clips.

When approaching a red laser alert beam, quicksave. Blast the explosive barrels with a shotgun as a vortigaunt teleports in to eliminate it. A second vortigaunt may appear and can be dealt with similarly. Alternatively, sneak past the laser.

Deal with the two turrets. To take out the first, bash the wooden crates next to the large green crate stacks to get a line of sight, then shoot its leg with a pistol. For the second turret, go around the right side of the green crates, bash the wooden crate there, and shoot its leg.

Hop onto the green crate stacks, using a jump-crouch maneuver for the highest crate. Drop down past the stacks and run through the fire door. Jump onto the next green crate stack. If fast enough, you can drop into the next area (section c1a3d) without being caught by teleport-in headcrabs.

Crouch-walk on the wet floor until you can see the first turret around the corner. Shoot its leg until it falls. Repeat for the second turret, which is farther down near the fire door's button. You can also try using hand grenades or charging with a shotgun.

After disabling both turrets, check past the fire door for any unexploded tripmines on the left wall and shoot them with a pistol if present.

Go through the fire door to find a first aid station and boxes for supplies. Climb a ladder to a walkway with more boxes.

After another ladder, get your assault rifle out. Move along the walkway until you can look down into a room with a hostile marine. Open fire immediately. If damaged, return to the previous room for health and armor.

Go to the lower floor, find an aid station and assault rifle clips on a green crate (and a rifle next to a dead marine). Press the button next to the large lift to open it. You can have a scientist follow you and then slam the lift doors on him. Ride the lift up; section c1a3a will load.

After the lift stops, stay back as a scientist runs forward and is shot by three marines. Stay in the lift with your assault rifle and shoot any marines on the upper walkway.

Find the dark passageway to the left as you exit the lift. Dodge grenades and shoot marines with the assault rifle. Marines may enter this side area with you.

Try to kill the marine on the upper walkway with the pistol first. Then, wait near the side area's entrance with a shotgun. When a marine nears explosive barrels, blow them up. Finish off any survivors with the assault rifle.

After all three marines are down, search the area for wooden crates to bash for supplies. Use first aid and HEV stations if needed, or backtrack for supplies.

Find the stairs to the upper walkway. Go through the fire door and across a bridge, watching for barnacle tongues. If they are difficult to avoid, shoot the barnacles with the assault rifle before passing under them.

Optional Shortcut: Use a barnacle whose tongue dangles close to the bridge. Quicksave, let it grab you, hit it with the crowbar, and lean forward to land on the bridge. Turn left to find a walkway above the room with the exit lift. If you take this shortcut, kill the marines below and skip to the last paragraph before section c1a3b.

Past the barnacle bridge, you'll reach a path split. Ignore the laser tripmines to the left and go down the ramp to the right. This leads to a large area with crates, barnacles, and a conveyor belt. There is a higher floor with crates and marines. Toss grenades onto the higher floor.