Other mistake: When Ferris first arrives in the town the the church bell chimes seven times indicating it's 7 o'clock. Later the bells chime again but this time only four times indicating 4 o'clock. Surely he didn't walk around the empty town for 9 hours.
Suggested correction: Since the revelation of the episode is that Ferris is merely in a simulation, it stands to reason that they control how quickly time passes for him.
Other mistake: When Mike first walks into the town he sees the ringing church bell then looks to his right. The camera acting as his POV pans from left to right but since he was already looking to his right then the camera would be facing the direction he just came from.