Take out your Nikita Launcher and shoot the missile directly across that room. Press Triangle (PlayStation version) after you shoot to guide it where needed. Take a right down the room and then a right around the corner across the room through that doorway (which appears to be difficult to get through), right in the room in the doorway, then left at the generator. Note: Watch out for shooting cameras. You can repeat this until you are successful. Go back and forth when air gets low out of the room.