Certified does mean she can swim, that's all she had to do once she was on the surface. If she signaled that she was OK to the instructor at the surface (we don't know if she did or didn't) and the boat crew had her next to the boat (at the ladder) I see no problem with the instructor leaving to get back to the other divers.
I think it is clear to everyone that she had to do something more than, "just swim." She had some other, unexpected, problem ... and that's what you need a buddy for, that's why you don't abandon a buddy or a student, certified or not.
If one of the other divers had a problem, everyone would have been screaming, why did he leave the group at 100' on a wreck. I believe he did the right thing, he saw her to the surface, got her to the boat, then got back to the other divers asap. I've seen divers hang onto the ladder for 10 minutes before climbing up.
I have no problem with the instructor transfering responsibility to a crew member for watching her board, whilst standing by to assist, it that (in fact) happened I'd shift my complaint to the crew member, but in either case, someone let her down ... big time. An unwitnessed fatality, at the surface, in the sort of situation this appears to have been is, IMHO, clear evidence of a negligent breach of duty, even if she had a massive coronary and was gone even before she fell back into the water.
These are the special rules for this forum:
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(4) No trolling; no blamestorming. Mishap analysis does not lay blame, it finds causes.
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Clearly there is no rule against speculation or hypothesis, although to speculate without clearly limited facts seems unwise. There is a rule against "blamestorming."
In my opinion it is too soon to really form any opinions about this accident. If a crew member did not jump into the water, there may be a very good reason. Remember the first rule of rescue is to avoid turning one injury/death into two.
It would be helpful if the folks nearer to this keep an eye out for more information in the local media or even do a little digging so we can all learn from this.
Jeff
No "blamestorming" here, just sound analysis: If responsibility for assistance had been shifted from the instructor to the crew member and the crew member was not prepared to handle the duty, either due to a lack of skill or the conditions, that still leaves the operator holding the bag for the Captain's decision to proceed with the dive. Had the crew member been attentive, had the diver suffered from a medical problem, and the crew member witnessed her falling back into the water and made the conscious decision that was too dangerous to enter the water and tossed a marker or ring, that would be one thing, but not knowing where the diver was or even that diver was having problems is unacceptable.