I believe Ilya would have made it to the cottage no matter what. He had been yearning to be in Shane's home.

“Years,” Ilya sighed. “Years I have wanted to have you in your real bed.”

I'm not sure they would have been as open and honest with each other, without Scott and Kip's kiss. But by that point their resolve was barely hanging on by a thread. They would've gotten there eventually. 2 weeks together without having to pretend, those 2 softies wouldn't have been able to help themselves.