I tend to think that if there were any feeling either had toward each other, they were present earlier on than some of us think. I keep going back to the closing scene in "Collision". I still think that scene was key. When Eric and Nat were talking to each other outside the elevator, I think the same thoughts were going through there minds-"Wow! This could be something more!" They hit a few big bumps in the road which threw them off course, so to speak. A few on this thread put it out there that Eric was a hare's breath away from falling hard for Natalia. This is something I tend to agree with. I also think he became conflicted, here was this great woman that he wanted to be with, but on the other hand he wasn't sure if he was ready to give up his "player" days just yet. And as Rissa said both of them had some issues. I would also think that Natalia has watched Eric for some time in the wake of his brain injury and can, in some ways, relate to his struggles. Given that she probably had some of her own after she left Nick.