Karyn's original decision to wear the top was not influenced by anything other than her liking it.
Her behavior now is influenced by the movie. She's putting herself in the femle lead role...I had the idea of a scene where we see other moviegoers acting weird. But the effects of that will wear off, likely during her date.
Karyn will be even more suspicious when she realizes how she was acting, and more convinced that she needs to snap others out of it.
