"Is that the third question, or just curiosity?" He asks, intrigued. If she's curious, she knows at least some of the details already, if it's the third question, then she's asking it because that's the game.

"Because there wasn't any other choice. Sometimes, you can knock someone out, if you don't think they deserve death, but if they're working for the bastard you're after, then they're likely to be just as much of a bastard. So you put them down before they do it to you, or before they do it to someone else."

That's all there is to it, in the end. Sometimes, you have to kill or be killed.