Martin freezes for a moment when Jon actually takes his hand, his steps and expression both, for just a split second, going completely rigid- before he relaxes, and grabs onto Jon's hand hard before he has the chance to pull it away.

"Um, we were partnered up for some project together, and we just started hanging out a lot then..." His heart is thrumming in his throat. "There wasn't any real - catalyst or anything." He's not acknowledging the hands.