Originally Posted by ani90
My understanding is that these masks are virtually useless and can not provide life sustainable oxygenation in true emergencies in a depressurizing craft.
You don't need sustainable oxygen. You are going to need it for about 2 or 3 minutes because your plane is going to be in a serious dive down to 10,000 feet or so. Even if you don't get it on at all, you will quickly pass out but you might still survive because you will get air back soon. Oh, don't risk it, put the mask on before helping others.