All statistics, but also videos are against your hypothesis. The string won't be cut if you shoot in the mouth. I don't believe in the survival instinct, because if it existed, suicide wouldn't exist. I believe there is only fear and people are afraid even of a life-saving surgery. It's paradoxical, isn't it? However, in countries where guns are easily accessible, gun use ranks first in suicide. This is because you don't have to think about it too much, it's the long waiting time that makes the suicidal person restless. In countries where weapons are difficult to find, the first method of suicide is hanging. The speed of suicide always wins in statistics. From suicide by jumping onto a moving train, to suicide by jumping from great heights. But where the weapon is accessible, that is chosen.