Lived all that time and still too stupid to figure out how to die?
There are ways to obliterate yourself if you want to. eg, build a machine that cuts off your head, dashes it to tiny little bloody cellular bits and incinerates it and the body. Don't tell me there's any coming back from that.
If you're going to argue that wouldn't work somehow, then if you lived for a few centuries you can't tell me you couldn't come up with something equally or more thorough and final.
I mean in the movie it depicts them whining about not being able to die and it never even addresses something as simple as what happens if the head is cut off.