This is exactly how I'd want to watch a death metal band. With them locked inside a soundproofed box. Watching them play until they pass out sounds fun but I doubt it will work like that. They'll start by getting confused, then headaches then they'll probably just have to sit down and stop playing but I seriously doubt they'd ever get to the point of passing out.
They'd pass out from excess carbon dioxide exposure before they run out of oxygen. Their rescuers might have enough time to get them out and revive them. If that's the plan...
http://www.thestranger.com/seattle/burie…
You scientifically illiterate fuckers are lucky you didn't have a dead body on your hands that time.