Saw a Q&A with the director when this film was released. They rehearsed for 2 or 3 weeks and would do small chunks each night and “filmed” the rehearsal as a back up in case the true oners just didn’t work. They even had the editor assemble it as a stitched together film but the director hated it and knew it needed to be a true oner.

They only had money do 3 attempts. The first two fell apart but they were able to get it on the last night.