It’s a bold filmmaking choice to have a countdown clock on the screen for most of your movie . In the best-case scenario for a movie like “Mercy,” in which a Los Angeles detective has prove his innocence to an artificial intelligence judge within said time limit, it heightens the tension. Who hasn’t gotten sweaty palms in, say, a “Mission: Impossible” movie when the bomb is ticking down and Tom Cruise still hasn’t cleared the building? Why not just extend it for the duration? Perhaps in a