: I've been able to grenade hop onto the lower box in the middle of the room
: with the "light source" polygon, but the damage (even on Easy)
: precludes a second shot. I tried lateral wall grenade climbing to the
: higher box which leads to the corridor above, which Narcogen referred to
: as a "red herring". Two shots and I splash onto the floor. I
: wonder if anyone has been able to survive wall climbing (with or without
: cheating) and get onto that raised poly and into the corridor?
You might already know this, but you can access that corridor another way---via one of the two rooms with water where you jump down and the drones start attacking. The room I am talking about is the one adjacent to the secret room with lots of water.
You will need to jump into the raised pool on your right. You can get there without grenade jumping as follows: Start in the water below this raised pool. Then run forward and left towards central walkway, and right when you hit the walkway, you will get a slight bump in upward momentum, which is just enough for you to immediately turn right and jump into the raised pool. It takes a little bit of practice but isn't hard at all.
The raised pool is actually a secret elevator that goes up a short ways. Once you're up (don't fall off!), there is a secret door to your right (if you are facing the wall), and behind this secret door is the corridor that you are trying to access. At the end of corridor is some AR ammo and the room with the light source polygon.
