"Emily?" Calvin said, projecting absolute calm in the face of her frenzy, despite the fear gnawing away inside of him. He waited until she'd definitely stopped talking and hopefully was looking at him before he continued. "It's okay, calm down. It was just a kiss, it doesn't have to mean anything. You're overreacting."
His brain had almost caught up with events and one thing was clear: his first priority was not to lose Emily as a friend, and if that mean pretending like nothing had happened, then that's what he would do. "It'll be easy to never mention it again because I've completely forgotten what you're even talking about," he said, moving forward like he was going to touch her knee and then pausing and then deliberately continuing the gesture. Pretending like nothing had happened.
"It must have been something about..." It took effort to think back to before that moment of impulse, the feel of her lips against his -- "Jacen and Katie? I mean, and Annie having--" He gave up on that sentence, the thought of Katie momentarily silencing him. He'd barely noticed Emily talking about Katie because he'd been too worried about her tone of panic, but he'd heard it and it had entered his subconscious and mixed with his own thoughts only to sneak out again as a Freudian slip. But thoughts of Katie just confused him, like they had been doing ever since he and Katie broke up.
"We were talking about not being able to change the future," he decided. "And I never saw that so it couldn't have been important." That probably didn't make sense, but he didn't really care at this point. As long as he said it in a calm tone of voice, that was all that really mattered. "We'll just be who we always were, just like we promised."