Ethics are subjective.
Say, if for example someone is about to fly a plane into a Skyscraper, the cockpit door is closed tightly and you can’t get in, even if the person is armed, you have a gun, you can kill the person and open the cockpit door… You would save many life’s, in exchange for just one… Whats unethical about that?
I think you are kinda insane, at the wars end most German soldiers where literally underage, there is no justice in killing them, not the smallest bit.