I don't get it. Why doesn't she scream? Why would ANY woman put up with that shit? If I were her, I'd turn around and punch him in the face and knee him in the crotch.
In Japan there is the cultural/social pressure to mind your own business and also not make a scene and bother other people. Unfortunately that means that it can be difficult for a Japanese woman to feel like they are able to take action in this situation.