Johnstone was so impressed with Amie's portrayal of the killer doll with no prior experience that he wanted to tap into the areas she was already skilled in.
He encouraged Amie to work with dance instructor Kylie Norris to create a dance that was "creepy, but also kind of distracting." The two delivered five or six soft choreography options for the scene, which Johnstone describes as "all very strange and not what I had in mind at all, but they were all kind of great and weird and disturbing."
Once he was happy with the final sequence, he "snuck the moment into the film to see if anyone would say anything."
With the dance now an absolutely iconic moment from the film, it seems Johnstone made the right call!