Actually, I see it just the opposite.
She knew Lelouch back when he stayed with Suzaku, so she also knew Nunally.
Todou also knows Lelouch, probably not to the same extent, but still...
And GWOtaku, didn't you say during episode 15 it was wrong for Lelouch to have those children killed? They were Rolo clones, if you want him dead, why should they be spared, they have the exact same minRABet, or perhaps different, but still warped.