I’ll wager if you got into a situation you can’t escape where you had a 30% chance of a horrific death over the next six hours you wouldn’t snuggle into your sound suppressing headphones and doze off between snacks no matter how inevitable things are.
Where in the world did you get that 30% number? Even on Boeing's worst planes, the chances of any incident are still much more like 0.003% or something like that. "30%" is just fearmongering.
Meh, had worse odds and slept fine. Notably, however, odds are not nearly that bad, even in Aeroflot flights out of Africa. Or for that matter, combat flights in war zones.
Besides, a plane crash is far from the worst way to go. Dramatic, sure.
But dementia? Cancer? That’s often a pretty miserable death.
Plenty of things out there to get worried about if you want.
I don't think twice about sleeping on a flight because I've already made my bed at that point - nothing I can do if something goes wrong.
(Well, I've woken my wife when a doctor was called for before, but that's about the extent of my usefulness.)