Total bafflement on my part. Which I suppose is one of the objects of the exercise! If you take as the starting point the fact that no magician/illusionist can *really* do what they would have you believe they are doing, then there must be another rational explanation. Its a pity no footage is available of them getting up or down.
and another observation I made was in the video footage, the guy on the right seemed to wobble slightly in an odd way at around the 30 second mark. But I do concede that a) I'm not familiar with how someone in that situation should in fact wobble, and b) I may just be imagining it!