Word gets around, eventually, about things that happen in Milliways - sometimes it takes a few days for the information to make it to the 'right' people, but it'll usually get there.

When Carl hears vaguely of what happened out in the woods and the abandoned, ruined hospital, it takes most of his willpower to keep from bolting straight upstairs to Jack's room and breaking down the door. As it is, he hurries down the hall and finds the right number, and knocks in a familiar pattern that Jack should recognize as an old 'code' of theirs.

He hopes Jack is still in the bar and hasn't gone back to his world yet...