When we get on a plane, we know the drill.  Once we are settled into our seats, in a matter of minutes, the flight attendant will go over the safety drill.  Early into those remarks, we are told:

“If the cabin pressure changes suddenly during the flight, oxygen masks will automatically drop from the compartment above your seat. If this happens, pull one of the masks down to your face and cover your nose and mouth. Slip the elastic band around your head and tighten by pulling the loose ends at…