After getting secrets #1 and #2, as shown in the previous section, you're now on the MIDDLE TIER OF THE AQUEDUCT, above where you killed the first 4 bats (4-7) at the beginning of the level. Go into the dark room ahead. It contains many shallow alcoves.
One of these—the second on the right—has a small medi pack (14). Grab it and return to the openings overlooking the area below.
Jump from the left opening to the building ahead on the left. Two more gorillas (24-25) are hiding ahead: one in the second alcove, another in the farthest. You can probably kill the first one from safety by jumping across the gap to get its attention then back-flipping to the ledge where you started.
For the second, advance to the next-to-last alcove, wait for the gorilla to emerge, get a pistol lock...
...and backflip away firing. Just be careful not to fall off the high ledge as you fight..
NOTE: If you go quickly, you can kill the first gorilla, then jump over to the alcove with the large medi pack, shown below, and shoot the second gorilla from across the gap. If you lose your footing here and Lara survives the fall, you'll have to make your way back to the ROOM WITH FIVE SWITCHES and retrace your steps through the SAND ROOM to the TOP OF THE AQUEDUCT. Then drop down into the pit where you found secret #2 again.
After dealing with the gorillas, turn to face the rock wall across the gap. You'll notice a large medi pack (15) in the long, horizontal crevice in that rock wall. Take a running jump to grab the flat part of the crevice near the medi pack and pull up. If Lara won't pull up, traverse a little to the left where the ceiling is higher and try again. Take the medi pack.
Then drop back to grab the edge and traverse all the way to the left. Drop onto the flat corner block.
Roll, draw pistols, and kill 2 bats (26-27) that fly out of the alcove on the other side of the gap. Then take a running jump over there.
Follow the twisting passageway up a series of ramps and ledges...
...until you emerge in a cave with 3 break-away floor tiles (28-30/51).
You'll want to shatter all three for the "After Us The Deluge!" achievement/trophy. Run across the first two tiles to the niche on the right with the large medi pack (16). Pick it up.
Then run from the safe niche onto the third cracked tile at the corner, where the gap is small, and keep running onto the solid floor. (Or, take a standing jump onto the cracked tile and quickly run on to the solid floor.)
NOTE: If Lara falls through, she'll land safely in the pool at the end of the aqueduct, near secret #1. You'll then have to swim/climb all the way back here.
DARK MODE: Even with brightness adjusted, dark images on a light background can be hard to see. May I suggest a reputable dark mode browser extension, such as Dark Reader? (Download only from trusted sites, like darkreader.org or your browser's web store.)
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