Jagasaki noted earlier that he felt like he had crossed a line he shouldn't have by choosing to kill the 5 strangers. I suppose this is part of the change he felt inside of himself. Once you open the door to killing innocent people to get what you want, one does have to wonder what limit there would be to that choice.
Maybe you're okay with killing 5 innocent people to save a loved one, but what about 500, or 5000 people?