On the pedestal to the far right is a blaster rifle. Get it if you like. If you miss, swim to the ramp at left and wait for the pedestals to reset. To get across the room, Force jump ahead, left, right, right for the blaster, or left and aheasd to the opposite gallery. Once across the room, exit and head down to a long tube with a rail in the center.
Force push the guards as needed.
Go right to a room for GEBs. Exit and go right. Left to another room for more GEBs. Exit and turn left to a lift and press the button to go down. Exit lift and go left to a long tube.