Chest 1 (Element of a machine gun)
While escaping from the location, at the moment at which you climb out of the water - the chest is in the next corridor.
Chest with coins 1
Right in front of the entrance to camp Archive chamber, at the corpse on the right.
Chest with coins 2
At the sculpture in the big chamber, where you found the atlas.
Chest with coins 3
A moment before you swim through the opening, past which you need to dive, between the sharp rocks on the right side of the cave.