Right inside the door, to the left, a computer gives off sparks. Shoot it.

When you arrive here (the rotating wall behind you), give the container on your left a shot. Goodie inside.

When you are on the moving platforms in this room - or rather, when you fall off - go to this ledge. The water goes deep there. Dive down, to the back left and up. There is a dry room with some goodies.

When you get to the hangar well, jump in the water. At the end of the platform, there is a underwater opening.

This is at the very end - the lift to the next level is to the right. Shoot the wall at 'X'.