I am pretty sure that was my issue as well.
There is one other part of that description that piqued my interest, although it did not appear to have been a factor, and that was the rapid ascent in the rescue scenario described.
I once played a rescue victim during a scenario in which the diver was supposed to bring an unconscious diver to the surface. This was being done at nearby Rock Lake, where I could settle down in a weedy area and appear to be unconscious. As I lay there with my eyes closed, I felt the rescuer get on my back and lift my inflator hose. Then I heard the rush of air as he pushed the button for all he was worth.
I knew what was going to happen next, so I immediately began a full force exhale that lasted all the (very brief) time it took to get me to the surface, where I broke through like the submarine in Hunt for Red October. It was scary, frankly. The instructor conducting the class and I later discussed the need for an emphasis on safe ascent rates in the pre-dive briefing in the future. (The student had done it correctly in the pool, but...)
A lot of people don't realize that, according to Boyle's Law, air expands more during an ascent at altitude than at sea level. I calculate that at Santa Rosa, air expands more than 10% more going from 34 feet to the surface than it does at sea level.