I just returned from the liberty 4-28 cruise. I don't know of a secret door. If you go to deck 9, port side all the way foward you will see a door with a port hole shaped window. Go through that door and open the next heavy wooden door and you will come out onto the deck just above the bridge. It is a great spot to see the entire side of the ship as well as the crew deck below. It is also a great vantage point to watch the arrival and departure from port.