Help. I move trough the caves on chapter 'The Fall', after destroying GLaDOS, and then I get to a place full of water, so I go trough a ship's door that is broken, but trough a hole I can make a portal. Then I am in the main elevator room, where there is a recording by cave johnson. I can't get to the other part of the broken bridge, and don't know what to do. Also, I can't go back to the water room.