Koeryn said:
Q: Do You think you could take a life to defend your own.
Yes. I can only guess how I'd feel about it in retrospect, having to kill someone isn't the kind of thing you take lightly or forget, but I would do it if I had to.
Koeryn said:
Q: Would having a friend or family member's life on the line with yours make you change your reaction?
No.
Koeryn said:
Q: Would the difference between the up-close kill, and the point and click of a ranged weapon have a difference on you?
No.
Koeryn said:
Q: Would having a stranger's life on the line with yours make you change your reaction?
No.
To those who say they would make an effort to only injure/incapacitate their attacker, not kill them, I have something to say:
If, as the OP's question suggests, the situation has degenerated to the point where your life is in danger and your only option is force, you're asking to be killed if you "go easy" on the attacker and use anything less than lethal force to stop them. If you shoot someone in a "non-vital" area, there's no guarantee that it will incapacitate them right away, just as there's no guarantee it won't kill them a few minutes later, after they've shot back and killed you. There are good reasons police don't "shoot people in the leg just to stop them".
1:
There is no safe place to shoot someone. Shoot someone in the shoulder in real life and it's unlikely that it'll just incapacitate them for a while, and they'll be up and about the next day with their arm in a sling like in the movies. Depending on where it hits, the bullet could destroy the ball-and-socket joint in the shoulder, leaving the subject's arm useless, or it could ricochet off of the scapula and end up in the chest cavity, or it could nick a major blood vessel. In any case you could still kill the person.
2:
It's easy to miss. A bullet is a small thing and it's very easy to miss your target, especially in an adrenaline-charged, "kill or be killed" kind of scenario. Soldiers and law enforcement officers are trained to aim for center of mass (i.e. the torso) for a reason, it gives the highest chance of hitting and incapacitating the target.
You might try to shoot an attacker in the leg, hoping to just incapacitate them. Assuming you don't miss, the bullet may sever the femoral artery. That gives your attacker a few minutes to live, in which time they may retaliate and fire back. Result:
You're both dead.