Well the truth is a matter of perspective. Witnesses will give their interpretation of the events based on what they saw or thought they saw.
The "torn" BCD could have been a result of a diver's knife cutting it off to get quick access
The DM (if he was indeed a DM) may have had no experience splashing in these types of conditions.
The Surgeon may or may not have said he could tell it was not a running prop. He may have seen more of an impact injury and less of a slashing/cutting type injury.
The O2 was either used or not, working or not.
I would certainly expect anyone worth their salt coming out of any of my O2 provider courses to have got the O2 on if at all possible. Head injuries always deserve O2 as does anything related to the circulatory system (bleeding) and the Respiratory system. One would expect the respiration to be shallow so O2 enriched air to the unconscious breathing Casualty is always advised.
I'd say we shouldn't get too hung up on some of the statements of "witnesses" who were on the boat or spoke to someone from the boat.
There is a lot of value to discussing the potential contributing factors in the incident. Some of the things that could contribute to an accident like this.
Inexperience in High seas. We all need to give serious thought to what level of seas is too dangerous for US to take on.
Inexperience with Hot Drops. Was the concept clearly explained. Did the person listen to the brief and follow it? Were these conditions too much for the "Hot drop" experience of the diver? Is there a way to get a bit of practice at Hot Drops, should that be done before the trip?
Could something have distracted the diver? Another diver they were watching out for.. sea life?
Was enough research done on the type of diving in the area and the appropriate training needed prior to committing to the trip?
Did anyone actually SEE the event .. the impact or is it ALL speculation?