When completing everything in the Villa, and starting the Gala, I went in the casino, but then left it (don't remember why) then when I tried to go back in, nothing happened. Has this happened to anyone else? Please help! I want to continue the main story instead of DLC.

How did you get out? Don't the lobby doors lock once you go in?

If you really don't want to play more of the DLC, I'd load up a save from before entering the bunker.