The stranger makes Jack promise not to tell anyone. He fears that if the others discover the truth, they'll believe he's a spy, but he insists that he's been removed from the "flock" for trying to help her. This could explain why he was not present during the first week. He says if they find an escape, he wants Jack to take the Mysterious Acolyte along.

Jack may choose to believe the stranger or not. If he chooses to take the Mysterious Acolyte during their escape, he might need to convince some of the other characters if they mistrust her since she'll be difficult to disguise or hide. Despite the stranger's request, Jack can involve other characters he trusts with this secret in an effort to help, or he may betray the stranger if he wishes.