Rather than diving into an abstract and theoretical discussion I wanted to use a simple example that everyone can relate to as a entry point to discuss and understand team dynamics. That attempt has obviously failed.
Skimming over the thread, though, it seems like there's been fairly useful information given out.
I'd like to give my $0.02 though which is:
#1: team failures are team failures, and everyone has issues to work on with the team separation there.
- buddy doing the valve drill needs to not be so task focused and needs to be able to maintain awareness of both other buddies. this lack of awareness is probably an indicator of lack of skill with the valve drill and probably going a bit too fast into doing valve drills, not getting a more stable platform first, not getting your head up, going too fast or some other issues.
- buddy doing the valve drill needs to be aware of positioning and not be drifting off. a lot of the time 'drifting off' actually is more about kicking and flailing quite a bit during the valve drill which indicates that the diver really needs to slow down a bit and work more on fundamentals before trying to whip through valve drills.
- buddy immediately watching the valve drill is there as the safety diver, but also needs to be aware of positioning and the third buddy.
- the third buddy needs to be close. all of you should be roughly an arms distance from each other and able to donate. the third buddy needs to not be shy in valve drills and s-drills and needs to close the gap and get in to the point where ideally elbows are nearly touching.
- the awareness of the third buddy on location was good, but the prioritization was bad. team comes first. the third buddy can signal to get back into position but this will interrupt the drill. it really needs to be decided beforehand how much shifting in location can be tolerated and how much interrupting of the drill can be tolerated. if divers are new to valve drills they may want to just acknowledge that they'll drift in which case i'd want to see just an awareness of how much drift was involved in the dive and what the cause of the drift was -- if the diver was uncomfortable and doing a lot of kicking, or if there was sideways current or other issues.
the overwhelming issue seems to be here that the divers were focusing on different aspects of trying to do the drill correctly. eventually we want to be able to put together the drills so that everything gets done correctly, but when starting you're going to have to triage what you care about a little bit -- and you're going to have to communicate those goals as a team.
and i'll stress this is a pretty common problem. i was doing a valve drill one time in the dark at 20 feet in about 50 feet of water when i went onto my backup and found that it had been crushed and was breathing water and i dropped to the bottom while my buddy focused on maintaining a reference at 20 feet and we were separated while i had no breathable gas. later we found out that the better way to deal with vertical separation is to maintain a reference for your buddy as long as you're not +/- more than about 3 feet, and to *communicate* immediately on swings out of position of no more than a foot.
focusing on 'i need to be a reference for my buddy' is only good when the team is together, and it needs to involve more communication as that separation increases -- it needs to be discarded when the separation is putting the cohesiveness of the team into jeopardy.
again, i'd suggest for what you're doing to keep the team together, then possibly communicate drifting (e.g. signal "look" and point at your reference object) and then to debrief afterwards, and work towards improving and minimizing drift in the future. and *most* likely if you fix trim and buoyancy and comfort with the valve drill you'll also find that the 'drifting' around fixes itself too.