Sarika involved in the mercy killing of her mother.Unless her mom is still alive,being in ashok's custody.
Sarika involved in the surrogacy scam.Ashok is its head.Hence entered bhalla's house upon ashok's orders.
romi will not be able to father a child again has been sarika's lie so that she is accepted in the bhalla's house.Once again ashok's idea,hence controlling sarika now.
Sarika involved in rinki's murder.Highly unlikely.But may have been an accident.But ashok knows this and is using sarika .
But in all the above cases,sarika is controlled by ashok and hence using her for his personal gains.
Surrogacy card will play strongly and shagun will expose ashok's hand in it.Sarika will be forgiven when ishita explains her motive.And shagun the ngo wil reveal how she pretended to be a surrogate to enter bhalla family and expose ashok using sarika.She wil praise ishra for the love they have for each other.wish them well.
ULTIMATELY SHAGUN WILL WIN.THERE WILL BE NO SURROGACY.MARK MY WORDS.