Part 31

Go back down the ramp and through a "SURFACE ACCESS" door. Enter the room with a first aid station to be knocked out and have your weapons stolen. You'll wake up in section c2a3e.

As soon as you regain control, quicksave. Run forward and jump onto the boxes. Carefully crouch-jump up the boxes to reach a side ledge without falling.

Wait for the trash compactor to stop moving. Quicksave and quickrestore to ensure its halves display correctly. Use the compactor halves to cross the room and grab the crowbar from the ledge on the other side.

Climb down the nearest ladder. Use your flashlight to find a floor grating, bash it open, and drop into a large pipe. Follow the pipe to reach the "Residue Processing" chapter.

After falling into water, turn right and exit the water. Go through a tunnel to a large outdoor area. Two headcrabs will appear; run into the area and swerve left into the water to avoid them.

Run-hop across the water to a silo-like structure with a ladder.

Go to the right of the silo to find a valve wheel. Start it turning and immediately run up the ladder. Quickly drop onto the lowering wooden platform before it descends too far.

Ride the platform until it stops, then crouch-walk into a rusty pipe opening. Follow the pipe until section c2a4a loads.

At the end of the pipe, bash open the grating. A security guard will kill some headcrabs. Follow the guard, grabbing his pistol after he is eaten by barnacles. Collect the bullet clip on the floor nearby.

Use the crowbar to bash the three barnacles the guard leads you to. Use the first aid station on the wall past them if needed.

Go down the hallway to the left of the first aid station to find another bashable barnacle near the top of winding stairs. At the bottom of the stairs, watch out for two headcrabs to the right.

Return to the room where you dropped from the pipe. Find the ladder on the side of a large hazardous waste vat. Climb it and jump to a chunk of gunk ahead, then take a running jump to a pipe entrance past it, crouching before landing.

Follow the pipe to a ledge in a room with waste vats and mashers. Jump onto the nearest masher as it rises from the sludge, then jump to the second masher before the first re-enters the sludge. Immediately jump onto the large pipe past the second masher.

Walk along the pipe, turn right, and jump to another big pipe. Follow it to a waste mixing vat.

Before crossing the vat, drop to the lower floor. Use the first aid station. Go through a door to find an area with two headcrabs and an HEV station. Defeat the headcrabs and use the HEV and first aid stations until you are at full health and armor.

Climb the ladder back up next to the mixing vat. Jump to the center of the nearest mixer. Wait for the mixing arms to align, then quickly jump to the center of the second mixer.

Run forward to land on the edge of an open pipe. Crouch-walk into it and follow it until section c2a4b loads.

In the room with conveyor belts, bash wooden crates for health and ammo. Ride the large slanty conveyor belt.

After dropping into water, turn around and enter the large underwater pipe marked with a "DANGER" sign. Surface in the next room and get onto a side ledge.