In open water training, we should have all learned to breath from a free flowing regulator. It`s important that divers practice those skills in a confined environment about once a year. It`s just as important to have gear suited for the conditions of the dive. Near freezing water requires gear that is designed not to freeze up. I`m not sure of the specifics of the diver`s deaths...but it`s always a good idea to remind everyone about safety, training and proper gear selection. And in life, nothing is 100% guaranteed...no matter how safe we try to be. The only way to limit your chances of getting hurt is to stay inside, and that`s no fun.