Egypt - Temple of Khamoon (part 8)
Tomb Raider Anniversary - Visual Walkthrough
Climb up, lateral jump on the door, and the quickly back jump.
Lateral jump again.
And jump to your right to grab the ledges.
Once you get up, you may want to get the supplies. You do it by shooting the target, and when the hook comes down, you use your grapple to get there and back.
Then continue on forward. Grab onto the accessible ledge.
Climb up.
Kill the mummy.
Go through the door and up the other ladder.