Sorry if this is a repost...
There was a point in "The Making Of TII" on VH1 when Michael was sitting where the audience would be. He was watching the Thriller part of the movie to see what it would be like to see it from the audience's point of view. On the stage, there was a stand-in where he would have been. They showed this twice. I thought that this was interesting.
Edited to add: I'm not sure if the stand-in was performing or just standing in where Michael would have been.