As per the new article Barkat was an extra in movies. So I am thinking, what if Mir has hired her to act as Barkat...It would make perfect sense...maybe even that hitting her drama was staged coz she took Zain with her on purpose to meet Mir.
She cudve easily sneaked out alone too...when no one was looking..I think it was planned that Mir will try to beat her and Zain will become protective...