Have two people on Xbox Live fire rockets at the sniping nest at the same time and it should fall. Make it tumble into the water so that it disappears. Have someone in your party leave so you get to the "blue" screen, where it says "Setting up game" and reloads it. Once the game resumes, go back to the sniper nest, as it should be back. If you shoot at it now, all bullets will go through it, as if it was not there. However, players will still be able to stand inside of it without falling though.