@Rainboe - "warning toxic" is well merited for you. Glad you have a genius IQ even if the rest of us (including this Cambridge graduate) don't.
I am tired of people assuming that pax would have passed out and died.
Do you not realise that most people can survive (and remain conscious) for 1 or more minutes without oxygen?
Freedivers better than myself can do it for up to 7 minutes!