Haha he didn't threaten her. Actually it is his way to take her emotions. Because he has seen her vulnerable side and he understood that he has to force her so that woh atleast usse baat share kare. And yes he is a good actor too the way they are acts in front of other reflects how much pro they are.
Actually he said na he should get benefit and he wanted her his gf not because of this plan but because he was attracted like usse apna partner mil gaya tha. And pramod ke wajah se atleast susheela ka temper low ho gaya hai .
Plus I feel sumod wanted their personal life not to be exposed in front of other . Tabhi dekhna jab woh ek saath hote hai especially alone they are so comfortable and carefree and they share everything.
Plus chachi ko problem ho rahi hai sumod ke relationship se as she is thrilled that she isn't getting that respect then woh susheela ko kaise. That is why woh baar baar bolti hai ki pramod ke papa involved ni hote just to reflect that they should treat her just how do treats her.
I am talking in context of Episode 29 re! His words did make her momentarily numb and so did us. We were like: Ye kya hogaya bande ko? Aise kyu baat kar raha hai? He cleared it out, audience agreed, Susheela still had that fear for a few days then she realised he is trustworthy. Wo fear usne daala tha..he could have dealt it another way when confronting is all I feel. I am not denying his effects on her or what happened later. Just those words were not exactly indicating a request and writing for that episode could have been better đ