'Below Zero (2021)' is a thriller in which a prison transport bus is attacked by a mysterious stranger, leaving its passengers - a police officer and the inmates he's transporting - trapped inside. It's a straightforward sort of thing but it does exactly what it needs to, proceeding at a fairy propulsive pace and providing several engaging action scenes. It's often exciting and suspenseful, with a variety of enjoyable set-pieces, and it comes together in a satisfying way that blurs the line between right and wrong. It's a little predictable, but that doesn't matter too much. Neither does the fact that it features a few logical inconsistencies. It's an entertaining experience from start to finish. 7/10