Dr. McDonagh is named after
Martin McDonagh. Writer/director
André Mileti was working as a set PA on
Three Billboards Outside Ebbing, Missouri (2017) simultaneously while filming
The Mark (2017) on weekends. Similarly, the lab rats are credited as "Nicolas" and "Victor," a reference to filmmaker
Nicolas Winding Refn and executive producer
Victor Ho. Mileti worked with the two on
The Neon Demon (2016).