Chapter 10. Reside Processing [Black Mesa]
10.1. Acid Treatment
Help the guard fight off the headcrabs. Proceed forward through the narrow corridors and close the valve to stop the fire. Take the pistol from the dead guard and restore health at the stationary first aid kit. Go downstairs, grab two clips of ammo, and restore health at the charger. This is a dead end; we can't go any further.
Return to the first room where we met the guard. In the room, climb the ladder, pass over the acid tank, jump onto the pipe, and enter the open ventilation shaft. Crawl to the left and jump over the wall on the other side. Grab the pistol and battery ahead.
We'll enter a room with tanks filled with bright green acid. We need to get to the opposite side by jumping on the moving pistons (it's best to go on the right side). Continue down the corridor and into the next room.
We see two acid tanks ahead, with rotating mixers inside. Turn right, follow the pipes, reach the end of the platform, jump onto the rotating mixer in the second tank, and from there onto a platform with a door.
10.2. Water Treatment
Below, we see a wide stream of water. Dive into the water, swim through the tunnel, and emerge in the next room. Continue along the narrow path to avoid the thresher in the water. After it, jump into the water again and swim forward.
We'll find ourselves in a room where fire periodically appears from pipes above the water. Dive deeper here to swim under the thresher. Immediately beyond it, we can emerge at a dead end on the right. At the end of the corridor, we'll find a supply of first aid kits and an assault rifle. Swim to the end without turning, and emerge.
On the surface, we'll grab the magnum from the dead guard. We enter the control room, kill the crocodile monster, grab a couple of batteries and a couple of explosives, and press the lever on the wall. We climb up to the room above, restore our health and energy, and press another lever. We jump onto the moving conveyor belt.
10.3. Conveyors
On the conveyor, you'll need to press another lever to proceed. In the next room, you'll need to jump from conveyor to conveyor, lower and lower, to avoid the shredders.
At the end, jump onto the pipes, enter the control room, press the green button, and use the lever to move the platform to the center. Jump along the platform into an open tunnel.
Ride along the conveyors again, gradually descending. Take the lowest conveyor into a dark tunnel. Ride outside and begin jumping from one parallel conveyor to another to avoid the shredders.
Descend to the room with acid in the center. Jump onto the platform below, climb up the ladder, and then another. " Questionable Ethics " begins.
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