Other mistake: When Johnny and Mark save Denny from Chris R., they claim they are taking Chris R. to the police station. However, they re-appear in the scene almost immediately after (within 2 minutes of screentime, which is meant to be in real-time), with their having been obviously nowhere near enough time for them to have taken Chris R. to the police and done the appropriate interviews/paperwork.
Trivia: Director Tommy Wiseau shot the film using a dual camera-rig. He shot the film on both a 35mm film camera and an (at the time) new HD movie-camera, both mounted to the same rig so they could more-or-less get similar angles, as he didn't quite understand the differences in the mediums and wanted to experiment shooting the film with both simultaneously.
Trivia: Greg Sestero is called Mark as a misguided reference to the actor Matt Damon and his film "The Talented Mr. Ripley." Writer/Director Tommy Wiseau was very taken with the film, and decided to name a character after Damon... however, he misheard "Matt Damon" as "Mark Damon" once during a conversation, and thus wrote the name "Mark" into his script for "The Room" instead of the proper "Matt." He never bothered to change the name to "Matt", thus making his intended reference null-and-void.
Johnny: Of course, what do ya think? They already put my ideas into practice. The bank saves money, and they are using me, and I am the fool.