You'll easily get to hang around for the show if you've finished but by the time you're seated, order drinks, and go through the buffet line I bet it'll be pretty close to showtime. I'd guess the show lasted 20-25 minutes.
EDIT: or are you worried about other people waiting around so you won't get seated? If so, I wouldn't worry, the band plays often enough that most people will probably have already seen it. The tables turnover pretty quick and there are a lot of them.