Part 50

Follow the "02 COOLANT SYSTEM" signs until you reach a hall blocked by rubble.

Crouch-walk past the first large piece of rubble on its left, turn right, jump onto a piece of rubble on the floor, move to its other end, turn left, and proceed through the door ahead.

In the next room, equip the gluon gun. Open the door and quickly kill the grunt directly across the room.

Alternatively, if crouched when opening the door, altfire-hornet the explosive crate on the grunt's side of the room, then fire hornets over the large white hanging thing. If hornets go up, sneak forward to altfire-hornet the barnacle over the upper walkway.

After the first grunt is dead, switch to the hornet gun. Back up slightly after opening the door to help keep the grunt on the right side of the room from seeing you, then sneakily hornet it.

Enter the room and use altfire hornets to kill the three barnacles, one of which is on the upper walkway.

Check near a dead scientist for health packs.

Find the "COOLANT TANK 02" sign on the wall. Place a tripmine in the center of the second wall segment to the right of the sign.

Climb the ladder and move cautiously along the walkway until the third grunt teleports in and falls through the walkway ahead. If the tripmine is placed correctly, it will explode. If not, quickrestore and try again.

Jump over the walkway break and proceed to the door.

Past the door, use the wheel on the right wall to turn off the steam.

Crouch-walk through the rubble and go up the stairs.

At the top of the stairs, turn left and quickly hornet-shoot the two headcrabs on the walkway ahead.

Use your flashlight to find the third headcrab on the floor near the big orange pump machine, then hornetize it and the three barnacles on the ceiling before dropping to the floor.

Get armor batteries near the dead scientist if needed.

Use the pump machine's red lever to start it.

Use the ladder to return to the walkway, then go back the way you came.

Revisit the downstairs room with the scientist and supplies if needed.

Go the other way from the hall T-intersection and approach the door you were previously told to bypass.

Quicksave, then open the door and run through it.

In the middle of the room beyond, run and drop into the water at the bottom of the large tank quickly to avoid being horneted by alien grunts.

Find the maintenance access tunnel and swim down it. When you enter a small room where you can surface for air, section c3a2b will load.

Swim through the tunnel to the base of the reactor core.

Look up and left to see the head of a vortigaunt on the lowest ledge circling the core.

Look around underwater for two small flow control valve wheels on the walls.

Use one wheel, wait for the water level to stop rising, then use the other wheel.

After the water stops rising again, float on the surface where the vort cannot zap you and wait for it to be zapped by a core electrical discharge.

Climb the nearby ladder to its top, then look up and locate the stray electrical bolt moving slowly above you.

Right after it passes, climb onto the ledge, turn left, and run for the next ladder.

Quicksave near the top of this ladder.

When you climb onto the second circular ledge, turn right and run for the nearest ladder, watching the multiple moving electric bolts to avoid getting zapped. Quicksave again after reaching the top.

On the third and final circular ledge, turn right past the ladder, jump a gap in the walkway, and run for the alcove with the door.

Wait until just after the electrical beam that hits the center of the door goes off, then go through the door and run to the right.

Go down the corridor until section c3a2c loads.

Go through the "SUPPLY D-301" door and check the shelf.

Enter the malfunctioning elevator and climb the ladder in the back to elevate yourself.

At the top of the ladder, turn around and jump to the broken elevator door to reach level B.

Go through the "SUPPLY B-301" door and check its shelf.

Leave the supply room and go down the corridor to a door on the right leading to a room with a security guard.

Go past the door and turn right. Walk up to the crate ahead, then immediately back up until you are by the security room door.

Have the shotgun ready to double-barrel the vort that teleports in slightly to the left.