I've heard someone describe suicidal ideation as like being halfway through a multiplayer game where you are getting stomped: It's not that you want to rage quit, it's just that the outcome feels inevitable so you wish you could skip to the end. Or like turning off a ball game early when your team is down by an insurmountable points at the end of the third quarter.

For at least some people, it may not be that they want to die, rather it may be that they predict 30+ more years of an unsatisfying life and wish that they could just skip to the end.