Jack hates Irina for screwing him and Sydney over time after time again. Enough is enough for Jack and he would not hesitate in the least if the chance was ever brought up again.
I think Jack would never actually bring himself to kill Irina-I think i he is mr emotionally detached because he still loves her so much,and that is what bugs him so much.
I mean it's been like 20 years and the guy still hasn't moved on...he has no new wife or girlfriend,no friends to speak of and can barely give his daughter a hug.
Look what happened when they went on that mission and they ended up kissing!!!!
I don't think he would kill her,he's just hurt...to quote sydney...you loved her so much you lost your soul."
that my friends says it all.
