I think Irina really loves Syd. She just doesn't show it all the time because she is like one of those strong and silent types exept, she's not that silent.
Irina so loves Syd, you can tell from just the way she looks at her, so moving and so proud. Even if she does have some issues, killing and all, she loves her daughter like any mother. In her case more as she never got to see her daughter grow up!
And i think that when we saw tears int Irina's eyes when she was talking to syd, it was like apologies for what she had to do and for the pain she would do again to her...