What the heck....I'll throw this one in for consideration even though it was not me doing the rescue. Two months ago I was diving a wreck in Fla with (3) other divers. Our dive plan was to descend in a group of four but pair up with a single buddy to explore the super structure. The current was blowing pretty strong and our dive was to begin at about 100'. Soon after we began the swim my buddies remote SPG stopped working so we called the dive off. The other two divers carried on with their plan to swim the upper superstructure.
Once back on the dive boat, our attention was called to a diver who had surfaced on a mooring ball 100' to our starboard. He indicated that there was diver OOA on the line. I recognized his voice as being one of the divers in our team. After a brief discussion we determined that the OOA diver was not with our group but was sharing air at 20' with my other partner.
Long story short. My buddies were swimming the wreck when a panicked diver came out of nowhere and snatched the reg from one of their mouths. He was likely a little narc'd and was pointing to the reg signaling a problem. In retrospect, we think he had the reg in upside down and couldn't clear properly. He was taking some water. He was also hyper-ventilating and over breathing the reg which made him even more uneasy. My friends kept him from making an emergency accent and started slowly up the line. At about 55,' he sucked the that tank dry. The first freind then did a controlled ascent to the surface to report the problem while the other buddy began sharing his air. After 1.5 minutes at 20', he drained the other tank.
Once back on board, the OOA diver stated that he signaled out of air to his two dive partners. They pointed him to the nearest line. According to his partners, he swam in the other direction. When we asked why they didnt follow him or call the dive off, they answered that he couldnt have been out of air because they had 1800psi and one of them responded that they didnt want to leave the third diver alone.....huh? According to OOA diver (possibly narc'd at the time) he ran across two photographers and signaled out of air. They refused. That's when he ran into my friends.
My friends were all done diving for 24hrs do to the lack of an adequate safety stop ruining their plans to make (3) more dives that day. In my mind and in that of the OOA diver, these guys are heroes and saved a life. The OOA diver paid for their dive and was very grateful.
What went wrong from my POV:
1) You never leave your buddy!!
2) Calling a dive off is not negotiable
3) Know and dive within your limits. This was not a dive he should have been making.
4) Dive boat Captain should have administered oxygen as a precautionary step to the diver who surfaced from 100 without a safety stop.
5) Dive boat Captain should not have allowed the OOA divers buddies to dive the second dive on this wreck.
Other steps I plan to take
upgrading my 19cu pony to >40cu