As I understand it, you can pretty easily fuck up when distilling and leave the methanol in if you don’t know what you’re doing. The first bit of stuff that boils off and collects, the foreshots, contains awful stuff like methanol and acetone. If you don’t remove this you’ll have methanol in your moonshine (and also it will taste awful).
This probably wasn’t done maliciously, would be my guess, but rather someone was learning how to use a still and seriously messed up.
Edit: I may be wrong, it sounds like you’d have to drink a lot of tainted moonshine to die. So maybe this was malicious. Or someone accidentally served foreshots.
It’s physically impossible to open a door on an airplane during most stages of the flight. The door first needs to move inward before opening, and the pressure differential is absurd. The handle would break long before you’d open the door. The only time it’s really possible is near the ground as you’re coming in to land or taking off (which did happen recently).