Part 8

Continue down the corridor past the storage area filled with wooden crates.

Bash the crates and run over orange scuttlebugs until you reach the loading point for section c1a2d.

In section c1a2d, bash every wooden crate except for the very biggest one.

Crouch-walk slowly past the largest crate to position yourself to shoot the headcrab on its other side.

Bash the largest crate and proceed to where you can find a shotgun and shells on a green crate. You may need to jump onto the crate to collect all items.

As you approach the caged area with a security guard, a zombie will appear. Shoot the zombie once with your pistol to draw its attention, then let the guard finish it and open the gate. Alternatively, run to the gate and kill the zombie with the shotgun.

Before entering the cage, drop to the lower floor and bash crates to find a health pack and an armor battery.

Climb the ladder to the higher floor, enter the cage, and collect ammo from the green crate near the guard.

Talk to the guard to make him follow you, then proceed down the hall past the cage area.

In the next room, a headcrab is in an overhead vent shaft. Run to the back of the room to lure it out, then quickly back up and strafe to avoid its leap, allowing the guard to shoot it.

Collect all ammo in the room, then return through the cage gate to section c1a2.

In section c1a2, lead your guard to the D-AL 101 room's broken window so he shoots the headcrab inside.

Talk to the guard to have him wait, then crouch-jump onto the window sill.

Face the nearby table, hold the "Use item" key, and move backward to pull it towards you.

Once the table is next to the window, get back on the sill if needed and crouch-walk onto the table.

Bash the glass pieces out of the sill, then hop onto it and drop into the water. Quickly crouch-jump onto the table before taking significant damage. (It is possible to jump directly from the sill to the table without touching the water, but it is difficult.)

Jump from the table to the large counter on the right.

Jump over the sink in the middle of the counter (its water is electrified).

Jump from the end of the counter to the small table near the first aid station.

Jump to the small counter with the dead headcrab.

Use the light switch on the wall to turn off the electricity.

Find the vent shaft to the left of the light switch counter. Stand in front of it with your flashlight on.

Wait for the three headcrabs in the shaft to approach the grating and shoot them through it. Some may crawl down the shaft.

After killing all three, bash off the grating and crouch-jump into the shaft.

Before entering the shaft, go to the large cabinet to the right of the first aid station, open its door, and collect an armor battery.

Move through the shaft, staying crouched under a large fan. Headcrabs may drop into the fan and be eliminated.

When you reach a grating, bash through it and move forward to fall into a hallway.

Open the doors you couldn't open before and get your guard to follow you again.

Move down the hallway and take cover (press the cover button to crouch behind walls or objects) behind a large metal crate as your guard shoots drop-down headcrabs.

After the headcrabs are dead, tell your guard to wait.

Push the small metal box to be directly underneath the broken ladder in the ceiling.

Get onto the small box to jump to the ladder. (You may need to push the big box under the ladder first, then use the small box to crouch-jump onto the big box.)

Climb the ladder and move to a large bashable grating in the floor.

Bash the grating with the crowbar and ready your pistol to shoot the headcrab ahead as you drop down. (Alternatively, use your flashlight to find and shoot the headcrab before bashing the grating.)

Turn around and bash out the wall grating, but do not drop through yet.

Move forward until the autoturret to the right powers up, then quickly back up to avoid its fire.

Wait for the autoturret to power down after shooting a scientist and a headcrab, then quicksave.

Drop to the floor, turn right, and push the leftmost wooden crate as far as you can.

Bash the crate to move it out of the way.

Use the switch on the metal control box to turn off the autoturret.

Grab the bullet clip from the middle of the room.

Go through the red-outline doorway to the left of a dead scientist.

Check the green crate and shelves for ammo.

Find the red door and push it open to return to the hallway where your guard is.

Get your guard to follow you again.

Push and/or pull the small metal box to the turret room.

Use the small box to get onto the large metal box near the turret's platform, then jump to the platform.