Yes, I would kill someone if it meant my life would be saved
No, I would not kill someone even if it meant I would die
Only in self-defence
In self defense, I am sure I would. If it wasn't self defense, I am not sure but I think I might.
A free agent trying to kill me then i would try to survive. Not sure if the other person was being manipulated.
My life is far more valuable to me than the lives of any other human or non human creature.
The very notion of this idea makes it self defense indirectly, even if the other person was not threatening you. However, the court may not rule in your favor (see R v Dudley and Stevens - different justice system, but there's no reason to think it wouldn't apply)
While the lives of others are valuable, I would choose to preserve my own life over that of a stranger.