we really don't see her interact with sark but with syd, irina has like multiple personalities...the "I love you Syd, you are my daughter" mode and the "I'm taking down the opposition and bring the prize money home for myself" mode. like at the rink...she was really emotional, it was like "aww" they r bonding...until shes goes "i'm sorry honey.... " ::Irina elbows Syd in the forehead and knwos her out cold::
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Also I can't see Sark going "Mom..." while looking at Irina.