Just to clarify my concern ref flasks; I'm not so worried about the liquid spurting out at a cabin alt. of 8,000', my concern is what would happen to a flask of say 50/50 air and coffee that has been closed at 8,000' if the cabin suddenly climbs to 25-35,000'. You have enough problems in that situation without a thermos blowing up in your briefcase. Fire extinguishers etc are designed to withstand the pressure drop, not so flasks.