He wants to show Sam that Pakhi is not reason for their fight or problems.
Right now Sai leaving will mean Samrat questioning what might have happened between them and only thing would be Pakhi.
So it will be like undoing all Virat's action of whitewashing Pakhi's behavior as well as jeeva-shiva milan.
But in his rage, unknowingly, he is going to show his ugly side to Samrat due to this locking Sai drama.
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