I'm a rookie, so bear with me: I was once in a situation similar to that, and it astounded me how quickly everyone panics and the situation deteriorates. What I would do: grab my dive bag, throw my wetsuit in it, grab water bottles and put in my bag, put my bcd on, find a corner of the boat near no one, and wait until the last sec to pop off. In those last moments, you could think of something else to grab. The last thing I would do is make a run for life jacket. Everyone else will do that, may not be enough, will lose time in the congestion, someone may grab my stuff when I turn my back to it, etc. Inflate bcd manually. Wrap wetsuit around my waist, I can put it on when I calm down. Go into my bag where I keep large red inflatable ring (type that you bring to the pool). Blow up ring, put my feet up on it, so I'm horizontal on surface. Ive been in a life jacket, keeps you vertical, you use up energy by kicking your feet without thinking, and you are so low on the surface, you can't see anything. Ring allows you to get some vertical, being able to see further. Put your feet up on ring to get comfortable, could be many many hours before rescued. Need to conserve energy, don't move around alot. Tell myself to think like a winner, because many people get overwhelmed and just give up and die, so mental strength is the only think that keeps some people alive and others cave.