At its heart, "The Bullet Train" is a "bottle episode" elevated to a blockbuster scale. The vast majority of the runtime takes place within the confines of the Japanese Shinkansen. This setting creates an immediate sense of claustrophobia and tension. Unlike an open-world action film where characters can escape into the city streets, the protagonists here are trapped on a track, moving relentlessly forward with no way to exit until the final station.
The train entered a tunnel. Absolute darkness for three seconds. The Bullet Train Film