Heh. Irina sure didn't seem interested. No, absolutely not. I believe there's something a lot deeper that we're not seeing. Most people are misinterpreting the scene.
Nothing would ever happen between them. If it did, it was somewhere in the past and if that was the writers intention, then there's a reason why RR came to JJ and told him that he wouldn't feel comfortable with such storyline because Emily was the only person Sloane's ever loved and the only one who showed the human side of him. Having had him cheated on her (and Irina on Jack) wouldn't be such a good idea. And anyway, it was cut.
It was definetely an important scene though and it would've helped to understand Irina's motivations a lot better.