That's correct. Nobody on the team knows him in particular. He's going to be another runner entering in to this mission with their own endgoal and it'll be up to you guys to work it out and see what you want to do. The end goal, though, is to join up as a single team, in other words to have him join the group. You don't need to automatically gel or anything, but need to at least be friendly (and alive) enough to go on future runs together.