Sorry to chime in so late.
This also points to the dangers of being in close proximity to rope (aka line, guideline, anchor line, or whatever). I can't comment on anything else.
I dove a wreck in the keys, and found myself having to concentrate at the surface to not get entangled in the guideline from the back of the boat to the anchor line buoy. Quite scary in just 1 to 3 ft waves. Actually the line wrapped one full turn around one of my legs, and I immediately untangled myself, A definate potential ouch situation...at the surface...if it tightened up from the motion of the boat. It was a quite embarassing near miss, too. I guess moving along vertically was the way to go, as opposed to horizontally in a near face down position.
It just points out how dangerous a line can be when it goes slack (entanglement) or pulls tight (knocking out the reg or squeezing an entangled lim).