Why is it ok so long as it's not the people you know/live next to dying?
I kill (or assist those who kill), so that the enemy cannot perform his own plans on killing us. Of-course my own loved ones are more important to me than my enemy's! I would not think twice before killing one of the enemy's men, to save my own. That's just how human nature is - we protect what is ours, what we care for and love. I don't really see the point in your question.