"Good thing I wasn't waiting for you to ask me, then, hm?" He replied with a slight arch of his brow. He considered what she said about alternate universes and attempted to decide what he was doing by going back to her world. Was he creating a reality where he simply disappeared if he never went back? There would be heavy consequences for that, he knew, but that might not even be the case. All he could do was wonder, really, and he decided to be selfish and do what he wanted. After being tortured in a lab for months, he thought they had all earned it.
Before she had begun to speak about how this experience had changed her, he'd been about to explain that he didn't want to take away what she might have at home either. Instead he left the offer unspoken and nodded slightly in response.
"I'd like to go back with you, Lily. I'm certain. However, if we both wake up next to James, I believe we should come up with some sort of possible explanation ahead of time," while that was mostly a joke, he did suddenly wonder when or where, exactly, they would be sent back too.