Goof: When Joey goes to Ross's apartment for the second time, the corridor ends after his apartment. But after Joey knocks on the child's door there is a door and the corridor goes off to the right, just like all other times the corridor is seen.
Note: After Joey talks to the little girl he runs back down Ross's corridor and turns right into another hallway. Although Ross's apartment is in a cul-de-sac, there is a hallway just opposite the lonely old man's door. This is the hallway Joey turns into. The corner of this hallway is briefly visible as Joey leaves Ross's apartment, but especially the first time he goes there.