I did a show a few years ago that employed a revolve to use three different sets. One memorable night, at the end of a huge number where the whole cast was onstage, one of the cast members did not make it completely onto the revolve before it started to turn with the lights up. So, in a panic, she chased the set around, jumped onto the edge of the revolve with one half of her body on it, and the other half with leg lifted, this other half collided with the proscenium, and she went flying off DL into the DS wing. She was okay, and she finished the show a bit bruised and very embarrassed.