[he smiles a little, faintly] I could never justify ending a life. But it sounds like you recognize the difficulties there in teaching anything as a correct ethical standpoint. [even if her opinion differs from his; he hears her coming down on the side of "kill if necessary to protect others"]
That's why I think a class like this would be hard -- what's ethical and what isn't is so subjective. Do you already have your lessons planned out?