It's more insidious. At high altitude the drop masks don't provide enough pressure to maintain consciousness for their full rated duration. It's expected that

It's more insidious. At high altitude the drop masks don't provide enough pressure to maintain consciousness for their full rated duration. It's expected that pilots will descend very quickly after a depressurization event to at least 14000 or below. If he stayed at high altitude the passengers probably went unconscious quickly.