Part 49

When the lift stops, equip the hornet gun and push against the lift doors to open them. Fire hornets at a spot just beneath the large lambda symbol on the big orange sign ahead and to the left to hit an unseen vortigaunt.

Move to the back of the lift with your assault rifle ready and watch the passage to the right of the smaller "02 COOLANT SYSTEM" sign.

If a vortigaunt appears in that passage, shoot it down. If it moves to the left near a hallway entrance and an explosive crate, move close to the lift doorway and fire hornets to the left to make it move into the hallway.

Peek out and blow up the explosive crate with altfire hornets to kill the vortigaunt. The vortigaunt will not move unless it sees you, so crouch-walk to the railing to sneak-shoot it with the pistol if needed.

Approach the hallway entrance where two more vortigaunts are located. Shoot them with the shotgun, firing a double-barrel blast and strafing left for cover (press the cover button to crouch behind walls or objects). Strafe right when they fire and shoot them more, using the explosive crate in the hallway to help kill one. Alternatively, use an AR grenade to kill them both quickly.

Go to the back of their hallway, which splits at a T-intersection with two large signs. Equip the hornet gun to deal with three sets of teleport-in aliens.

The first set may have already teleported in behind you. Go along the left edge of the hallway until you can see a vortigaunt on a walkway to the right, near the "02 COOLANT SYSTEM" sign.

Let the vortigaunt see you, hit it with a few quick hornets, then back up and use the assault rifle to shoot it in the head as it approaches.

After the vortigaunt is down, move along the left side of the hall until you can see the blue "01 COOLANT REACTOR" sign ahead and to the left. Fire hornets toward the sign to hit an alien grunt to the left.

Return to the hallway intersection and turn right. Pass a security guard with a bullet clip on a crate, go down stairs, and through a door to find a room with first aid and HEV rechargers, plus ammo.

Return to the hallway split and go down the other way. Do not open the door at the end; run to its end and return to the T-intersection. This should trigger the second pair of teleport-in aliens. Repeat the process of killing the vortigaunt and then the alien grunt.

If the third and final teleport-in pair doesn't appear, go to where the vortigaunts appear, then down the ramp past that to a hallway with red machinery. Run back and forth in this hallway to trigger the final teleport-in aliens. Sneak-shoot them from near the bottom of the ramps. Repeat the hallway-running routines until all three pairs appear.

Get the security guard by the crates to follow you. Follow the blue "01 COOLANT SYSTEM" signs to a spot with two dead scientists.

Move past the dead scientists while facing them, as a vortigaunt will teleport in near them. Position yourself so the security guard is between you and the vortigaunt.

After the guard is zapped, shoot the vortigaunt with altfire hornets. The guard may help if he survived. If he is still alive, melee him for his ammo. Alternatively, drop a C4 satchel bomb near the dead scientists, back up, and detonate it when the vortigaunt appears.

Move to the door at the other end of the hall to open it. Stop and fire hornets toward the left side of the room beyond, targeting three alien grunts, one on a higher walkway. Kill them all from the doorway before entering. Be careful that none of the grunts see you when opening the door.

Climb the ladder to the room's upper walkway, go along it to a door, then up stairs and right to find the pump room.

Use hornets to kill the nearby headcrab. Move forward to see and hornet another headcrab on the lower floor, to the right of the big blue pump machine.

Move forward to the walkway split, then quickly retreat to the corner by the stairs.

Wait for two vortigaunts to teleport in. Move to a position where you can use hornets to sneak-shoot the one on the upper walkway to the right. It is easier to wait at the walkway split with the shotgun.

Crouch-walk along the walkway until you can use the crossbow to sneak-shoot the vortigaunt on the other side of the big blue pump machine.

Move along the side walkway and examine the pump machine with the flashlight on until you see its red lever. Quicksave, drop off the walkway near the red lever, use it, and run for the ladder back to the walkway. Two more vortigaunts will teleport in, but you can leave the area without being zapped if you are fast enough.

Make your way back to the hall.