Judging by this episode Lelouch isn't going to lose Kallen.
If she defects its going to be because she was lied to and forced to. Lelouch will only need to explain himself and she'll come back to him. Either that or the whole power of love cliche will come into play.
This takes a load off for us Kallenfags. No mindrape and no willing defection, she can came back and give Lelouch makeup sex, fuck yeah.