I'm planning on endangering another kid's life to save my own child.
What makes you think that you'll have to put another child in danger?
I'd much rather save my own kid as I don't even know the other kid.
It's expected of you to prioritize your own child's life over another that you do not know, but it is still wrong to endanger another child's life.  As long as you're not the one endangering his life, then you're fine.
What else do you expect me to do, ignore my child in trouble who needs help?
You should just do the best you can to help all the kids involved. Nobody has to be put in danger if you can do all you can to prevent it.