here is my version of confession.
After doing the surgery on Shruti. Sai along with her friends and Pulkit goes to medical camp near by. Where she will meet Sada and his gang members who will kidnap her along with few other students from the camp.
After the drama - that he will leave the CN, Virat goes to his and Sai room. He get phone call - number is not shown. He says "I will be there - don't worry - no one will follow. I will make sure." He waits until everyone is asleep and leaves CN. He gets in his cars and drives to unknown location - forest area. He is waiting when he hears sound and he take his gun out and he turns around slowly - the face of DIG sir is shown along with Sai and another men - who DIG sir introduced as ADGP Gupta head of CID.
Virat had told both Sai and DIG sir the Sada used him and his past friendship and his trust to take the vaada from him to make sure Shruti had the baby safely and faked his death, so Sada could make sure that he - Virat could provide the security needed for Sada & Shruti's baby safely being born since Sada also knew that Virat's wife Sai was medical student.
Maybe writers of the show bring this type of mystery and bring back both Virat - the IPS officer he is capable of and Sai who will do anything for her Virat sir.
Why was Virat and Sai involved in CID - what is Sada and Shruti crime - who knows.
thanks for reading