Climb out of the water on the ledge near the right door of the two identical doors on the west wall. Use the second RUSTY KEY in the keyhole here to unlock the door.
IMPORTANT: If the opening beyond the locked door is not filled with water, then you missed something. You'll need to flood the area, as described in the main walkthrough. If you've already dropped down into the spikes and survived, either reload an earlier save, or kill Lara on the spikes, allow the Passport menu to open, then page to the right for the Restart Level option.
Swim down through the spikes. (They're safe now that you're in the water.) Continue down and to the left.
In the flooded room below, look for another opening above on the right. Swim through...
...and pick up the small medi pack (20) lying on the floor.
Roll and swim forward to the GOLD KEY (21). When you take the key, the door to the left opens, and a crocodile (26) spawns in the room you just came from.
Quickly swim through the door and out into the MAIN ROOM.
Climb out on the nearest ledge and kill the croc.
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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