You can't save everyone.You are speaking now about life choices. It depends a lot. I guess I will leave my life for my parents one but not for a random one. This is a complex situation because law is supposedly to defend a life at all costs not sacrificing one to get other. This is a dramatic scenario and the worst possible dilemma.
"In the moment when I truly understand my enemy, understand him well enough to defeat him, then in that very moment I also love him. I think it's impossible to really understand somebody, what they want, what they believe, and not love them the way they love themselves."-Orson scott