Bani went inside and searched the whole of Pia's room, what did she expect, Pia to keep a file (files are so dear to KS) in which it would be written "Father of my kid-Mr.X"??
And what info can the doctor give Bani regarding the father of the baby? The doctor can know only about how the pregnancy is going, what can he tell her about MR.X? What is he going to do, match the genes of the unborn baby with every other genetic material in their laboratory?