It’s an interesting question really, and after much thought, I’ve decided that for me, it depends on the age of the child/children concerned.
Once upon a time, when my kid were littler (up until their mid-later teenage years) I would have had NO hesitation whatsoever in sacrificing my own life or somebody elses so that they could live. Absolutely no question. My kids’ survival was the only thing that mattered, and bugger the rest of humanity, really!
Now that they are a bit older and have ‘flown the nest’ so to speak, I don’t know that I could. It’s not that I love them any less, it’s just that the fierce, insane maternal-protectiveness chemistry has gone to some extent. I suspect that it will diminish even further when my kids have kids of their own, although that protectiveness-thing might be transferred to the grandkids by then. I really wonder if it is one of those biological imperative things that dictates that one must protect ones genes at all costs, even if that cost is the loss of anothers’ life.