Ironic isnt it, that it was somehow Shyam's doing that brought Bauji and Ammaji in Delhi in the first place.
I also wonder whether the scene where Shyam and bauji's medicine is also a potential plot to raise suspicion in the other members of the Gupta household.
Doctor has told Shyam the medicine. He gives the wrong one and causes a deterioration in Bauji's health. But why would Bauji take the medicine? He might be suspicious but takes it anyway. He might ask Khushi, Payal or ammaji to check his medicine. Khushi and Payal are intelligent and might realise that he has been given the wrong meds. They will question Shyam who lies through his teeth. Whether they believe him or not, a slight inkling of doubt is raised. Afterall, no one is more precious to Khushi then Bauji. And then once doubt is planted, the mind is more clued up to other inconsistencies and then like domino effect, the rest will fall in place.
(similar to Khushi now seeing the nice side of Arnav, and gradually will start seeing more)