system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: when a plane breaks up at 30,000 feet what happens to the human body, and how fast?

When Payne Stewart's plane depressurized, supposedly everyone died instantly but the plane did not break up. I have read on MH17 that people could be alive while they fell. I have also read about people surviving falls from broken up planes. Can someone explain what happens, what the differences are from a pressurization standpoint etc that would knock out pilots immediatley versus having people actually survive a fall etc?
gpt
At 30,000 feet you have about 1 to 3 minutes of useful consciousness, and more like 30 seconds to 1 minute at the altitude MH17 was at. What happens exactly? Well, you pass out. What happens then depends on the other specifics of the incident. In Payne Stewart's case, the aircraft maintained altitude, so when the crew/passengers passed out, they just remained unconscious until they died due to asphyxiation.

In the case of people falling from that altitude, they are likely to lose consciousness initially, then regain consciousness as they fall to lower altitudes with higher pressure. Would they be fully alert and aware as they struck the ground? It's certainly possible, but they would likely be only semi-lucid and in a daze of confusion.