the physician’s Crypt
Before leaving camp to go after this Crypt, make as many Hollow Point Bullets as you can. You can replenish your supplies of Magnisite quite easily in the areas coming up.
The entrance to this Crypt is inside a cave. Walk southeast from the Ruins Encampment, and jump over the walls so that you can explore the cliffs. The cave entrance is around an outcropping, so you don’t see it until you’re very close.
Go inside and break through a damaged wall. Descend carefully because you don’t have much light to go by. You reach a ledge that looks out over a major falls. Go over the edge and drop to the platform below Lara (do not jump out over the gap).
Use a zip line to go even farther down, and watch the ground as you advance. There is a Document on the left side of the corridor.
When you reach the bottom, swim down a tiny channel to your left. Open the Sarcophagus in the room beyond to retrieve a Broken Bow part.
Climb back out of the Crypt with your prize. On your way out, search the western side of the Crypt for a Mural. It’s up one level from the Sarcophagus.
the architect’s Crypt
Start at Ridgeline Base Camp and hop cautiously down the ledges of the cliff and waterfall. Use Survival Instincts to spot the ledges that are viable before you start your drop, and reload the checkpoint if you miss and fall into the water all the way down.
When you get onto the ledges, look for an Explorer’s Satchel and then hop underneath the falls. A Crypt entrance is there, inside a tunnel. Climb down into the depths and search the Crypt for a Mural, a Document, an Archivist’s Map, and a Sarcophagus. There aren’t any puzzles or enemies down there, so you’re safe to explore.