If I were you I would play the Naive Card. If she sees you and two together just act like it never came up.
I don't really have a similar situation but this does remind me of another situation.
Me with three friends, one normal, one psychotic, (the social life of an accountant blogging, clingy to the normal friend, trying to drive the group apart for him, and with a deep hatred towards me), and one that just gets carried away to often. Right now the group has split apart, separation from the normal (class schedules), the psychopath gone to a new school after me telling him exactly and bluntly telling him about his life (nearly suspended even though I gave him many warnings first, AND GETTING PUNCHED AFTERWARD, HELLO SCHOOL AUTHORITIES???), and me left there with the carry away guy as my one and only friend.