Could you kill an innocent person to save your own life?

This is morbid, so you should probably stop reading now if you're not comfortable with the topic. Sorry if it bothers anyone.

Now I know there's no way to know for sure how you would really react when put in these kinds of situations, but that's not the point. The point is to see how you THINK you would react. So be a good sport and really think.

So say you're put in a situation where you have no choice. It's kill or be killed. If you kill yourself it would cause the other person to be killed as well. Neither you nor the other person have chosen to be put in this position, but you're here now. This is someone you've known for several years. Someone you've come to know quite well. Could you kill them to save your own life?

Additional questions: does it matter if you know them? Like would it be easier to kill a stranger/acquaintance compared to a co-worker/friend? Or is it just something you couldn't do either way?