Scenario 1
Not sure how it happened, you could say that as it was a new mask the sportie should have had a spare mask, and the new mask should have been tried out in the pool first. A pony cylinder may have helped, if the regulator was easily accessible. Better practice with skills without a mask, such as mask clearing to give the diver some more confidence would also have helped, good skills practice in general might have stopped this. This is the incident pit in action!
I would question how likely with 2 experience divers this would happen, but I'm sure now I've said that 47 people will tell me of how it hapened to them.
Scenario 2
Put the casualty on 02, Nitrox if 02 unavailable.
Monitor the buddy.
Nominate someone to wrtie down time out of water, time on 02 etc...
Inform the Hard Boat what was happening.
Inform the Coastguard.
If you have a diver recall signal, use it.
If the coastguard decide a chopper is not an option, then as you have 2 divers left in the water, transfer the casualty and buddy to the hard boat and leave the Inflatable to pick up the 2 divers, the inflatable should be able to catch up without too much difficulty and might get a mile closer to shore, before being recovered. It would abviously depend on type of boats etc... the important thing to realise if you have 2 boats and therefore lots of options....
Just a few quick thoughts, oh and prepare to fill out all 4 pages for the BSAC incident report
