There's an expression that "there are no atheists in foxholes." I don't like this expression because I'm an atheist and I'd like to think I wouldn't capitulate like that, but who knows. I also once read a piece by an atheist soldier who claimed from personal experience that that statement isn't true. His words made me feel relieved. Still the saying stands.
A friend who's a chaplain and has seen a lot of dying people offers me this: "there are no religious in the throes of death." What she means is that even those who've lived their lives knowing that we pass on to a better place, still feel scared when facing their own time to go. I'm sure there are exceptions to this generalization (as there are to the other one), but I trust that it's true enough. Why would knowing that the arms of Jesus are waiting make it easy to leave the people you love and the only existence you know?
I've lived my whole life feeling scared, although I'm finally breaking free of those fears. I know what it's like to be in so much emotional pain that I wished I could die. But suicidal impulses still contain agency: you're in control. You're choosing to end your life. That's hugely different from facing a death that has come to you unwanted. How horrible to be fearfully dragged towards your own end, fighting the whole way. And yet that describes all of us, every day of our lives.