In the room with two holes, you can make running jumps over both if you time it right but you can make a standing jump over the second if you've run fast enough and still make it across. Jump over the hole in the last one and get onto the oddly colored wegde. The rushing water blasts the wedge, with you on it, to the cavern above. Now head over to the right until you reach a wall. Super-blast the wall and head right. Go up the stairs in the next area, then go to the right again. You pass by an algae covered area. This used to be a waterfall until you let the water out of the reservoir. Keep going to the right.
As you enter the top floor of the building, your friend pops out into a pipe beneath the floor. Watch for a few moments as he crawls forward and is stuck behind a metal thing in the pipe. Now go left back to the stairs and head down. Then go right, cross the ex-waterfall, and arrive in a room with chandeliers. Go down the stairs and when you're about 3/4 of the way across the room, a guard steps in from the right. If you time this right, you can zap him before he has a chance to react. Kill the guard, and head right. The next room has a teleporter at the base of some stairs about halfway up. Ignore the teleporter for now and go right.
As you leave the room, a guard punches you in the face, knocking you down and sending your gun flying from your hand. The guard picks you up from the floor and starts talking at you. When your head comes up, kick him (button or space), then run to your gun, crouch to grab it, and come up firing at him. Do it without pausing and you'll fry him before he gets a clear shot at you. After you kill the guard, go right once more. This room is really hard. You're in a corridor, as you reach the point about halfway between the first and second pillars, guards approach from both sides. My technique is to go a 1/3 past the first pillar, erect a shield to the right, turn around, crouch, erect a shield to the left, then turn back to the right and walk just far enough to make the guards enter.
Make another shield to the right, turn left, make a right shield, super-blast the left guard's shield, then shoot him. Turn right, make a shield, super-blast the right guard's shield, then shoot him. You gotta be quick to do this part. If you get killed, you start back where you see you friend in the tunnel. You don't actually have to kill these guards right at this point. You could do other things first and kill them last but I prefer to go after them first since the rest of the stuff is easy compared to these two. Now go back to the left to the room with the chandeliers. Stand at the top of the stairs and shoot the middle chandelier. This loosens the thing blocking the tunnel where your friend is. Now head left past the ex-waterfall, go up the stairs, then head right to where you friend is no longer trapped.
Make a shield about 2/3 along towards the right side of the room then head into the room to the right. As you enter, you see your friend slide past in the lower left corner and a guard enters on the right. Go back to the left past your shield, turn and wait for the guard behind the safety of your shield. Shoot the guard as he enters. Then go right. Continue right through the next room. In the next room, you see a fleeing guard. If you shoot at him, you'll just miss. Don't go down the stairs yet. Follow the guard into the next room to the right. In this room, the guard is hiding behind three doors and a shield. If you step through the door, he'll shoot you.
Keys für Revelation Online