I think I'd run out in front of a moving car for any pet - mine or not. Just as I'd run to save any human. I think its a trait commonly known as compassion for other living creatures.

I agree with you and have a hard time seeing your neice's side. In an event such as seeing a car barreling down on another life, you react instinctively... to save their life without considering the impact on yours. Just think that if you stood there and did nothing, and then stood there watching the animal (or human) being crushed to death. THAT would be worse for me than suffering a broken leg. My leg would heal, but the squished life wouldn't. There's no question what I'd do!