Like many others I have not seen an OOA diver and had read many threads that spoke of the panicked diver with the primary grab and even had instructors reinforce this idea. Then I read a recent thread that repudiate this claim.
One of those instructors is a well know cave diver with several rescues to his credit and I believe him. It leads me to wonder if a difference in the circumstance surrounding the OOA event plays a role in the response along with the divers training. No overhead, clear warm water verses more stressful dive conditions such as hard or soft overhead, cold and/or dark water or simply diving beyond experience or training.
Since there aren't many cave instructors with several rescues to their credit, I am going to take a wild guess about the one you mean. I know him pretty well. I have taken several classes from him, including DPV for the overhead environment. In that class he absolutely insisted that an OOA diver will panic and crawl all over you. He taught me a maneuver for OOA for divers on scooters that assumed the OOA diver will go after you. He was, in fact very much on my mind when I said above that I assume other people are telling the truth when they say say some divers, at least, will panic in an OOA situation.
I have talked with him about the circumstances in each of his recognized rescues and one other in which there is a dispute about the circumstances. In none of his rescues was the diver(s) OOA, although one was pretty close. In one of those cases, when he spotted the diver in the midst of a silt out, he backed away and then circled behind as a precaution in case that diver was going to go after him. That was probably a wise move, whether or not it was necessary. As I understand it, people were more relieved to see help than panicked.
What's the difference between those who will panic and those who won't? I can't promote any theory with any kind of certainty.
I think an obvious possibility is the difference between a highly experienced diver who is very comfortable in the water in contrast with a beginner who is not so comfortable. In the one case I was near, the OOA diver was a confident and reasonably competent diver, but she was not highly experienced, and she was in an AOW class (not from me). I am not convinced that is the best explanation.
I think a better explanation is not so much the individual diver or the kind of diving.
I think the major factor is the time between going OOA and reaching the donor. In the case I described above, she was swimming next to her husband, so it was only a few seconds between realizing she was OOA and getting a grip on his alternate. In the case the cave instructor told me about, the "victim" was a
highly trained diver taking a cave DPV course. He had been instructed that when doing an OOA drill, he should keep his regulator in his mouth and just pretend to be OOA. When he and his buddy had gotten a bit too far apart, the instructor told him to be OOA. Contrary to his instructions, he discarded his regulator as he signaled OOA and started motoring to his buddy. It took a bit of time for them to get there, and by the time he did, he was in full blown OOA panic and attacked the buddy for his air, even though he had a perfectly fine working regulator beneath his chin.
So I am going to suggest that if you have someone in an OOA situation, most of them, even beginners, will be just fine if they can secure an alternate quickly. If they can't, then what happens physiologically is CO2 builds up in the body, and it is CO2 buildup, not a lack of oxygen, that creates that panicky feeling that you have to breathe. If there is enough CO2 buildup, any diver will panic and potentially react irrationally, like that experienced cave diver who attacked his buddy for air even though he still had plenty himself.
