In message 200909281331238930-dplacourse@aolcom, David LaCourse
writes

Bruce said that we should blow out all the air as we rose to the
surface. He didn't say why. It wasn't until years later that I
realized how dangerous this "diving bell" was.

Yes indeed a simple mistake for the uninitiated but with possible long
lasting consequences. The trick would have been to surface no faster
than your bubbles assuming you were breathing out.

Air embolisms are nasty things.
--
Bill Grey