Pass the swinging burner in order to reach the end of the ledge.

1) Turn left and take a running jump to the opposite ledge where another swinging burner is (start running when the opposite swinging burner is on the left). Crawl through the opening and pick up the Flares and Uzi Clips.

2) Crawl back out and take a running jump back to the first ledge.

The crawlspace you entered this room should be on your right.

3) Take a running jump to the ledge ahead and a bit to the left. Crawl through the opening and use the first switch. No, this did not do anything, because you need to use another switch.

4) Crawl back out and, having the crawlspace to the back of you, take a diagonal running jump to the ledge on the right. Crawl through the opening and use the second switch. What just happened: this along with the first switch raised two platforms exactly below you. The second switch (as standalone) lowered the platform beneath where you got the Flares and Uzi Clips. Crawl back out.

5) Having the crawlspace to the back of you, drop to the block on the right hand side and then to the ledge below. Hang from the ledge and drop to the lower one in the corner.

You should now face another platform (if the entrance of this room is on your right. There should also be a long walkway on your right).

6) Take a running jump to that platform and then...

7) ... a standing one to the ledge below.

Turn right and you will see the third switch below. All the area in front of the double doors (the pinkish) is a trigger zone for fourteen wasps that will emerge from their hive above the pool. If you are not willing to deal with them, just avoid this area.

8) This means that you need to take a standing jump over this area in order to reach the switch.

Use the third switch to raise a platform exactly above you and a bit to the left (this platform will help you use the fourth switch).

9) Climb on the block to the left, walk to the edge and take a standing jump to grab the ledge ahead. Pull up and turn around.

10) Take a running jump to grab the platform you just raised and use the fourth switch.

The fourth switch lowers the platform you are currently standing on and raises the platform beneath the long walkway.

11a) Either side-jump to the left to land on the pinkish ledge, avoiding falling down or...

11b) ... fall down and jump to grab the pinkish ledge.

12) Having the fourth switch to the back of you, turn left and take a standing jump to grab the platform above (you passed from this platform before). Then, take a running jump to the platform in the corner. The platform you just raised is on your left, but you cannot reach it.

13) So, turn around and jump up to grab the ledge above. Pull up and climb on the block. From there, climb on the ledge in front of the crawlspace with the second switch. Crawl through the opening and use the second switch again. This raises the platform below where you got the Flares and Uzi Clips and it will help you get to the platform beneath the long walkway (you also lowered the two platforms below you, but you do not need them anymore).

14) Crawl back out and drop to the block on the right, then to the ledge below. Turn left and jump to the platform below where you got the Flares and the Uzi Clips.

15) You now need to jump to the platform beneath the long walkway and this is quite tricky. Walk up to the edge and take one step backwards. Take a standing jump without pressing Action (or you will grab the walkway) and you will land on the platform.

16) Jump up to grab the bars and traverse to the other side. Use the fifth switch to open the double doors and raise a platform next to the alcove. You are done!

To get down without losing health, traverse back to the previous platform, turn left and take a standing jump towards the hive, pressing Action to land into the pool below.