Why does David feel he has to obey the man and go north to Denmark, even though the man can no longer control him?

In Chapter Three, we learn that David based his decision to continue to Denmark on the truthful information the man provided him with. The man told him the truth about the bundle, and also about the method of escape..... thus, David thought the man must be right about instructing him to head to Denmark. David's decision was based upon trust.