In chapter 229, Christopher is dreaming. It is a recurring dream in which a virus transmitted by facial expressions killed everyone on earth except for people like him. Not understanding the meaning of other peoples faces, Christopher could not be infected. Now, as one of the only surviving humans, he can travel his ‘own’ world freely without being touched or screamed at.
For some, the thought of being the last human on earth might be a nightmare but for Christopher it is a dream.