Once you get into the deep despair, the rationality disappears. It's easy to logic "just do it without bothering others", but the reality is that once you're killing yourself, things like that don't matter much anymore. Then the logic can warp to "it's still better for everyone if I'm dead" or just "I have to die", or something like that. I don't really want to say the edgy thing, but I guess it is one of those things you can't fully understand unless you've been there.

Also it's really difficult to kill yourself effectively in a non-messy way, unless you have access to some proper drugs. My personal choice is hanging by cutting off your blood circulation, since it is very effective and you can do it without others seeing. Someone is always going to find the corpse (unless you manage to disappear in the wilderness for long enough, but then just disappearing is super traumatizing as well for the people looking for you), but in the best case scenario they'll just find you calmly in a sitting position and even though that's traumatizing as well, it's not brains splattered on the wall.

Killing yourself is always horrifying to others, there's just no helping it. I went so far I took selfies smiling seconds before just to make sure people left behind knew I was happy doing it, because that was the only solace I could give others in that moment