From the first room, near the striped pillar where Jean-Yves was tied, go between the gray columns into another similar-looking room to the left (south).

The camera shifts to draw your attention to a rope strung diagonally across the room.

Continue straight through and out the other side.

Turn left and climb the stairs.

At the top, turn right into a room with a lever and flaming sconces.

Use the lever...

...to open the gold doors down in the first room.

Then pick up the WOODEN TORCH in one of the side alcoves.

Light it on the nearby sconce.

Then return downstairs to the second room.

Stand on the left side of the room beneath the rope...

...and jump up and down to set the rope on fire. If this doesn't work, jump up into the alcove to get closer to the rope. The flame travels along the rope into the first room and somehow destroys a section of floor there.

Return to the first room...

...and toss the torch into the shallow pit to free Lara's hands. Pick up the Uzi ammo in the small room behind the gold door. Then drop into the pit. Follow the tunnel leading out of the pit.

You can bring the torch along for light if you like. Near the end of the tunnel, on the left, is an alcove on the left containing wideshot shells.

Toss the torch away (you won't need it anymore) and pick up the ammo.

Turn around and approach the doorway opposite the alcove.

[Citadel Walkthrough]