Exactly. And that King Air B200 that cracked a windshield at FL270. The pilots hadn’t actually tested the O2 as per the checklist (breathe in, feel the hiss/pressure) or even opened the valve, which had frozen shut from condensation. and when they woke up, airplane was in a vertical dive, airspeed was pegged, and by the time they pulled out, they’d bent the airframe and lost one of the elevators.