During the fight in the bathroom, the part wherein Johnny Yong Bosch knocks Eric Jacobus through a wall was unscripted. The plan was for the latter's head to dent the wall, but when it started giving way to the rest of his body, Bosch continued kicking Jacobus until he fell completely through it.
The cat seen in a couple of scenes was a stray that lived around the warehouse location. He was so friendly and cooperative that the filmmakers placed him in the movie.
Rebecca Ahn had broken her foot shortly before filming. She can be seen limping during a few shots in the museum scenes, for which she had to wear high heels.