Stuck in Route Canal

[Rune]

I have just got through the room where I had to turn the red valve and afterwards break the wooden planks art the bottom of a pool. I am the next room where I have shot two guys and I am looking for a way out but I cant find it.

 

[RAST]

I have just got through the room where I had to turn the red valve and afterwards break the wooden planks art the bottom of a pool. I am the next room where I have shot two guys and I am looking for a way out but I cant find it.

I don't remember which room you're in exactly. I think you're in the room where you have to walk over on the walkway above you....

Here's a great walkthrough link with pictures. It got me out of a jam or two:
http://www.hlfallout.net/articles.php/walkthrough_49/#walkthrough

HTH