Babita being shaken by the incident with Preet seemed like the much-needed trigger. She has been brave trying to make her life on her own, but still the idea that she was so fearful of such situations was bothering her.
The look on Hanuman's face when Babita said she wanted to learn to beat people up! đ¤Ł
He was probably thinking "What have I done? In my efforts to make her strong she's really going for it!" Of course, he was too polite to say anything to her face, I guess, but I am hoping they show him with a monologue on his thoughts about this latest development. As he had once said, Babita was Durga devi in making. I think this is what that behind the scenes video was about - the four ladies beating up some troublemakers. I really wish Preet would see this too.
I think this incident will cause the chain reaction in Babita that would lead to her finally wanting to stand up to injustice at every step in her life, not just when it happens to her but also to other women around her. So her slapping Ashok seems to be a continuation of that. If she had done it out of the blue it might have seemed odd, but the CVs are doing a good job of preparing us to see a more assertive Babita, so that the confrontation with Ashok would feel natural.