Unfortunately i believe i have been in the same situation as your friend Bob, it wasnt pretty to feel that way and your mind is clouded to what possible problems and solutions are (i guess until you have experienced it). We were diving the Speigel Grove, this was my first time in the Keys and on this wreck. The boat tied off on one line, but we were told to swim across current to the other boat to use their descent line. So we went out on the tag line and swam for the buoy (across current), i misjudged it as i was descending, but found myself taking time to get to the line, that worked up a nice CO2 hit and had my lungs going! Once on the line we dropped to 105ft in short order and made our way onto the boat. As we left the line and went more onto the boat i could feel anxiety, it felt like my breathing rate was up and my heart was going. I gave myself a few moments to compose, but it didnt seem to be getting better, i signaled something wrong and that we should turn the dive to my buddy, he came over and looked in my eyes (he said to see if i was panicky and that i wasnt) and off we went back to the line. We took it slow on the way up, and when we got above 80ft things cleared in my mind and it started to become obvious what had happened. All i can say is that my mind was fighting against the bolt to the surface anxiety driven thought that kept jumping around in my head. I knew i was pumped about the dive and i had heard about the currents on this wreck, but i think that also helped overwhelm me as well as the narcosis by CO2 hit. I believe i can see the kind of thing your buddy Bob felt, i hope i dont get it again, but i hope i have learnt from it.
