This time, instead of killing the Khajit again, I decided to take out Astrid instead. And now her last words - "Well Done!" have made me paranoid and insomniac.
Did I play into her hands by killing her? Did the Dark Brotherhood leaders in previous games ritualistically say the same thing upon getting killed (I don't think they did in Morrowind, but it's been a long time since I played it)? Or is this something she would have said if I had killed somebody in her presence, only this time that "somebody" was herself (which means this is a bug)? Most importantly, for my newly wed bride awaits me: is it safe to sleep?
A lot of other people all over the internet seem to be expressing the same doubts and uncertainties, yet no explanation has come forth.