Don, --This is not written in an attacking tone--
You have taken a beating and I'm sure you learned from it. I've been certified since 92. I'm not the end all beat all of divers by any means. For me it's a learning process on every dive. I draw from previous dives on what happened and try to recognize what caused the problem and be aware of it in the future. I'm working on my Divemaster currently and I am enjoying the challenges it brings.
You said you ran into a class on your way back. I assume this is where you lost your third diver. Personally I would not assume he went back down considering there was a mass of people. My first thought would be to sort out who is who. There is no reason to waste time descending 80ft when your not sure.
I dive with newer divers that don't have buddies quite a bit. I learn on every dive with them. I've learned that you can not assume anything about their training. Even if you know who trained them and trust that person, an individual still does not dive like that instructor that taught them. They don't know how I dive either. I'm usually laid back and take the dive at their pace. But they also don't know the local dive sites as I do, so I know I have to lead them a little. If the lake has lines from object to object, then I let the pair go first so I can see them and we move at their pace. If it's a compass nav to an object, it's follow the leader (not single file, but wingman, off to the side where I can see them at a glance), we decide who is navigating. If it's me, I go slow and still check on the other two often. If the vis is too poor (my judgement of too poor may differ fom yours), I do not attempt the compass with more than one other diver.
The biggest thing to learn is to communicate and observe how the other divers dive. If I see that they do not keep track of each other, then I take responsibility for that aspect and watch them. Usually it's not a big deal, I'm in the water, I'm not missing much since I've been there before. More often however, as new divers they don't want to get seperated either.
What would I have done.... You were in a lake right? You were all together at your safety stop and the training class was "doing skills on the lines". At what point in the safety stop did you get seperated? Personally I would have left the line with my buddies and stayed clear of the group and kept contact and communication with my buddies. I would not leave the line on a boat dive, but your less likely to have a class drop on you there. The other option is to stay on the line, let the group pass then ascend. An extra minute at the stop will not hurt you.
Backing up in the dive a little bit. The air checks. You can not rely on them to just come to you with their air supply. What if they have a better consumption rate than you? You can not assume you have the better rate just because they dive less. Your air is your concern, their air is on them, but sometimes in a dive a person forgets, they get to watching a fish or enjoying the view. Tap your palm or your gauge and ask how much air they have every so often (they should ask you too). This lack of communication foreshadowed that lack of communication later.
Diving with buddies is not a "hey I did my part" event. Sometimes you have to do more than "your part". I think you knew when you posted what went wrong and what you could have done different. But getting mad at the other diver was not right. You assumed what he would do based on what you would have done. He's not you. Was the other diver wrong? Maybe he is mad at you for leaving him. The best course there would not to have gone running and screaming at him. But calmly go to him and just ask, "Hey, what happened there?" Get his side, it make the learning easier, you then understand his point of view, you explain yours and you both learn.
Hind site is 20/20, learn from it to become a better diver and dive buddy in the future.
**If anyone disagrees with my approach, please reply. I'm willing to listen to your way and possibly adopting some ideas.**
