There was a similar incident here in the UK about 10-15 years ago. A diver in training in a sheltered bay, seemingly benign conditions. Underweighted so the instructor loaded him up with small trim weights and rocks, he lost control of buoyancy, the instructor lost control of the situation and the diver panicked and drowned. It wasn't an uncommon thing to do, adjust weighting on the fly using whatever you had stuffed in pockets, but I think this really woke people up to the dangers of doing it. The fatal accident inquiry tore both the instructor and the agency to pieces if I recall.
If it was another student, since they coujdnt find a quick release, how could they not know to unzip the BCD pockets to take out the weights? That might have helped even if she had weights in her drysuit.
Have you ever been in a life or death situation? Unless you're very well trained or very cool then most people have limited processing power available for analytical thought. Particularly as the key word here is "student". That puts a lot on someone in training. I don't know the circumstances but criticizing the rescuer for not thinking of something that is so outside of standard practice that even a fairly experienced diver might not have thought of it is undeserved. I'm not sure "checking the zipped pockets of BCD and suit for weights" would be my first thought.
About taking off the BCD and unbuckling the cylinder and low pressure inflator hose and breathing from that, then swimming up, would that work if a different situation if the person had a wetsuit?
Again, you need to consider the circumstances. You are in a situation sliding way out of your control, struggling to breathe, struggling to move (I'm guessing you also haven't experienced a severe suit squeeze), probably overbreathing her regs and getting gooned with CO2... this is not the time and place for creative thought. Lots of things might work, whether or not you are capable of a. actually stopping and thinking through the situation and b. executing that plan is a totally different story.
In diving, from basic open water to being a km inside a cave, you want your options to be as simple and robust as possible. Until you experience it, the mental tunnel vision that happens in situations like this is hard to appreciate.
So the answer is yes, it probably would work to some extent. But in reality, the likelihood of someone who feels like they are seconds from death and getting more and more physically incapacitated doing a Mission Impossible stunt is pretty low.
Just to give you an example, I watched someone below me manage to snag his equipment on the main ascent line in a quarry in Wales. He realised it, tried to free himself, didn't work, panicked, made it worse, panicked some more and... he just gave up. He literally just resigned himself to being caught there like a fish, gave up all attempt at thinking his way out of it and just hung there. He was on his own (single cylinder as well), he wasn't aware that I was there and he just gave up. The solution wasn't particularly hard but he just did not have the mental capacity left to find it.
This is interesting. I've always heard that everybody should have a quick release. Also, the open water course teaches with a quick release.
It's the received wisdom in recreational diving for reasons that might be as wrong as they are right. As diving gets more advanced then the need for a QR weight belt drops through the floor and the risk of accidentally having a buckle ping open far outweighs the risk of not being able to release it.
Also, as equipment loading increases then the actual value of a weightbelt becomes negligible. When I switched to a twinset, steel backplate and big canister light from a standard BCD, single cylinder and a handheld torch I went from something like 8kg to maybe 1kg just for comfort and could probably get away without it. I liked an extra kg or so for the end of the dive and putting that on a weightbelt is pointless, dumping it does nothing so you might as well just find somewhere on your rig to integrate it.
I hated QR weightbelts even when I was diving a single. I don't know how popular diving from RHIBs is in the US but in the UK it's very common and you will lose a weightbelt at some point either handing it up to someone or trying to get back in the boat with it on.
When I'm freediving I use a Marseille style belt which is easily removable but cannot release on its own. I've used it occasionally for the few times I dive in a single cylinder rig, far better than the standard webbing and flip up buckle scuba type.
