Now, he's too big for us to do this, not to mention too strong. And assuming that he still needs air to breathe while this thing is attached...
Get him in a room. Pipe out all the oxygen. He'll pass out first so they'll have to get him out fast. Fast enough, he'll start breathing on his own and be fine.
If they want to buy themselves extra time, pump in ice water first. He'll hyperventilate the first 1-2 minutes, then pump out the oxygen. If they do it after, he'll hyperventilate when there's no air to breathe.