Addendum, I was looking at:  to see if Dr Mitchell expressed his opinion there, but only found "Initially, the body becomes rigid and the victim loses consciousness. Breathing stops and the airway can become obstructed. If decompression (e.g. ascent) occurs at this stage a lung injury could occur." The observations concerning lack of expiratory obstruction seem to be post-2005 or so and may not yet have found their way into print. I'll keep looking.