We all wish. I think co and fsh, but you sort of need to get lucky, imo. Co may not work, so many stories on here of ppl surviving. And fsh you may black out quickly, but also loaded with different problems. Idk what others think but I suppose train or jumping from height may be so quick there's no pain, but certainly not guaranteed.
Recent thread had the question of if you could just push a button, would you. That's the dream. But no button exists.