When John Slattery inquires about Colin Robinson's accent, he guesses that he is from western Wisconsin. Mark Proksch was born and raised in Onalaska, which is, in fact, in western Wisconsin.
The orderlies in the Familiar Urgent Care wear the same square metal head cages as those in Dr. Seward's sanitarium in Bram Stoker's Dracula (1992).
Wilhelm Scream as Nadja tosses a "clinic" worker to the wall.
When Nandor is taking Colin Robinson to the convenience store you can see across the street is a pizza place called 'Staten Pie Land' but at 16:43 you can see the reflection for the actual sign 'Pizza Pizza'. This also reveals the filming location as Canada (Toronto) and not Staten Island.