Jack was somewhat frightened, but you wouldn't have been able to tell from his stoic visage. He knew it was up to him to convince them of their good intentions, otherwise he would probably be killed and the others would be killed or run out of town. This was a heavy burden for him. As much as he didn't care about the others, he still didn't want to see them die because of him. He walked on with the guards, praying things would go well.