After repairing the ANCIENT MACHINE and using the switch, as described in the main walkthrough, we'll go after the final secret. Drop into the water and swim downstream to the gold gate. Turn left and follow the stream past the ledge with the skeleton, where you found the SHOTGUN earlier.
Continue on the surface to the end of the passageway. Make sure Lara has full lungs, then dive under and follow the flooded tunnel through various twists and turns.
There are no side passages, so I haven't included screenshots for the whole sequence. Just keep going.
Eventually you'll be able to swim up through a hole in the ceiling...
...and surface in a small room with straw on the floor. This is SECRET #5: a small medi pack (14) and 2 boxes of shotgun shells (15-16).
There's no need to swim all the way back. Instead safety drop from the doorway...
...into the dry streambed. (Lara will lose a tiny bit of health, but all will be restored soon, when you enter the next level.) Follow the trench to the end (away from the gold gate holding back the water) and jump over the sloping rocks to fall safely into the pool below.
Climb out of the pool on a ledge that was previously hidden behind the waterfall. Follow the passageway to the end of the level.
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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