Burial Chambers - Secret #3

Avoid the area at the foot of the stone sarcophagus marked with the pink 'X'. It's not dangerous, but standing there triggers a cutscene and prevents you from getting the next secret. First explore the outside edges of the room, picking up a small medipack and shotgun shells in the northwest and southeast corners, respectively. Continue through the doorway opposite the entrance.

This passageway leads to the next room.

Here there's a seated statue and three smaller, painted sarcophagi. These are not dangerous...yet. Get the small medipack on the floor on the left. Then hop down into the pit in the northwest corner.

In a concealed room beneath the statue, you'll find SECRET #3 (16/70)...

...a small medipack and shotgun shells.

If you enter this room after triggering the cutscene, you can still get the small medipack, but the pits are filled with red liquid. If you drop into the pit in the northwest corner...

...there's a gate blocking the entrance to the secret. You'll need to reload an earlier save and try again.

Return to the previous room and approach the foot of the stone sarcophagus.

[Burial Chambers Walkthrough]