and sometimes you see things like this
changing O-ring 80 feet deep Holguin Cuba
[video=youtube;y6JgLB7Nlns]https://www.youtube.com/watch?v=y6JgLB7Nlns[/video]
I was with a DM when he fixed his own O-ring when it extruded. As soon as the eruption of bubbles occurred, he pulled off his BCD and shut off his air. When I saw what he was doing, I offered an alternate while I helped hold the BCD. He clearly thought he could do it all on one breath, but he did reluctantly take one sip off my regulator before turning his air back on.