Shirin can handle light hearted scenes well, but when it comes to emotional scenes her expressions fall flat. It's actually CVS fault to experiment with khi's character. It's an immature decision to give such responsible role for Shirin , when everything is going against EMA.
It would have been better, CVS kept pa-khi positive and end rakhi track properly. Then most of viewers would have liked her character. But to play a negative role she needs to improve her acting skills. To carry a positive character is easy, but to carry negative character is difficult job.