Swim forward from the starting point and surface in an UNDERGROUND POOL. To the left (east) is a ledge with some wooden crates. It's too high to reach from below. Ahead on the left (southeast) is a larger ledge with some barrels and crates. There's also a small boat moored there.
To the right (west) is a small waterfall. Swim behind the waterfall.
Surface and follow the passageway until it widens, but don't bother climbing into the raised tunnel yet. (It's a dead end at the moment.) Just around the corner on the left is a switch.
Pull it to open a wooden door elsewhere.
Return along the passageway to the POOL and swim across to the landing with the boat and barrels. Climb out of the water and follow the tunnel...
...to a cave with mine cart tracks and a drill car blocking another tunnel. Go to the left side of the rock pile behind the striped barricades. Pull the movable crate.
Climb over it and enter the passage behind. Here you'll find the door you just opened using the switch behind the waterfall. Beyond it is another switch. Use it to open another wooden door elsewhere.
Then return to the POOL the way you came.
Swim across the pool and behind the waterfall again.
Follow the passage past the first switch, climb into the raised opening, and continue through the now open door.
When you reach the ledge above the POOL, take a running jump to the ledge with the waterfall and striped barricades.
Continue along a twisty tunnel...
...to a cavern with a small building suspended from the ceiling. Lara will look up as you pass, indicating that this is important. Pick up the large medi pack (1) on the ground. Don't worry; the building won't come down yet.
In the glassed-in room on the left, there are 3 receptacles on the wall. You'll need to find 3 FUSES to fit them.
There's also some magnum ammo (2) on the floor in one corner (and a save crystal in New Game+, which you might want to save for after you find the fuses).
In addition to the passageway in the northeast corner, where you came in, there are two tunnels leading out of this cave. The small raised opening on the north wall is unreachable at the moment.
The wider tunnel to the west is where we're headed now.
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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