Normally when Kirk got upset he would just reach out and touch him, hold him even, but that seemed like a bad idea to do right now. Jim was already getting physical with him and simply upset with him being... well, himself; reaching out and touching him in a familiar fashion might provoke an attack.

"Jam-" He stops, rethinking in saying James's name at the moment since he looked ready to snap. "Seriously, it's me. It's me!" He was practically pleading for him to realize it was him, his mind racing to figure how to do that. "We didn't go missing five years ago, we ended up here; now."