In that previous shot it turns out Kylo was using some form of mind trick on a clearly distressed Poe Dameron (Oscar Isaac). The Rebel pilot's clearly a long way from home (and his situation in the rest of the trailer). We saw Poe captured by the First Order in the Comic-Con tease, and while this doesn't reveal much more, it's clear he's a prize catch for Ren. Which only asks more questions.