I don't think Jai will take advantage of her at all. I think it was a relaxant that Roshni tried to give Jai, and not a date rape drug, otherwise Bani would be unconscious by now.
I think the drug will cause Bani to lose her inhibitions regarding being intimate with Jai, and allow her to express her feelings openly. 😳 I also think Jai would never continue unless Bani gave her indication that it is what she also wanted.
And aren't we forgetting that the reason Bani is in such a state in the first place is because she suspects Jai is being unfaithful with Roshni? She wouldn't feel that way if she was not in love with him.
I also think that Roshni tried to seduce Jai, because she feels that he is slipping away from her, and she needed to establish a physical relationship with him again. In a way she could sense that he is being drawn closer and closer to Bani.