I don't think you got an option on that unless you kicked Anthony out at the first opportunity.Like the gang bang you're talking about I never took that action so she was never corrupted due to that event.
I forgot about her 1st experience with a gangbang, that was the aliens if you followed the 'weird shit' path.
The students at the gala were 2nd, if you took those choices and Anthony's was the 3rd gangbang if he was still around.