In jumping the grenade, the intent is exclusively focused on savng yhour friend, not on achievin deah for yhourself.
If, by some strange happenstance, neither of you died (neither you or your friend) --- say the grenade was a dud-- it would be considered a total fist-pumping win-win.
However, if a person tries to commit suicide and and they end up surviving, the suicide-minded person (and is/her accomplice)might consider that a dreaded complication. A glitch. That's because the person's death is directly intended. It is the whole point.
My MIL survived a no-kidding suicide attempt. Not clear how she’s seeing things nowadays from the perspective of her Christianity. I really don’t.
I’d be asking myself why I couldn’t kill myself, and then ask if there was still something I had left to do.
It’s funny, because they say you can’t add a single second to your life - when God wants you, He’ll take you.
The real question behind the question is whether any of us can truly know God’s will, for us, and otherwise.
That’s the advantage Christ had on us - he knew God, and knew God’s will. I think Christ would counter, “I’ve told you, I could tell you, and I don’t think it would matter - you are still going to do what you are going to do.”
Christ called the ball on Peter, and Peter knew better than anyone. Judas still outed Christ. It can make your head explode a bit.