Mountain Base - Getting Out of the Lantern Room

Now climb up onto the green duct and through the small, square hole high on the north wall. Drop down into the control room beyond.

Move to the right and use your axe to turn the red valve in the corner.

This starts the flow of flammable gas into the room.

When you've turned the valve, a Solarii with a rifle enters the room on the other side of the window and starts taunting Lara.

Now you need to get out quickly before Lara chokes. Climb back onto the green duct where you dropped down a minute ago. Then scramble back through the square hole into the previous room.

Quickly pick up one of the lanterns.

Move back from the wall with the square opening. Press and hold Aim. Then direct the arc so the end goes through the hole into the control room that is now filling with gas.

Then press Fire to throw the lantern.

Kerblam! 250 XP and one less obstacle in Lara's way.