[Kairu]

And, I'm going to add into the past/timeline thread here. I feel that if you go back into the past, you essentially create a mirror universe. Sort of the same concept "First Contact" used where in that even though the future the Enterprise crew knew and loved was destroyed, but because they went through time, and obviously a different future. But in turn, if you killed yourself in this dimension instead of yours, then you would, inevitably, have no effect on killing your present/future self because of that alternate timeline idea.