Bullet Train Parkour Action

Opening shot: a bullet train races through the mountains at night. The courier sprints along the roof. Suddenly the train enters a tunnel with a dangerously low ceiling. The courier drops flat and slides underneath while sparks explode inches overhead. Immediately after, another obstacle blocks the roof. With no time to stop, the courier leaps over it. The landing goes wrong. They slip off the side of the train, hanging with one hand above the abyss while the ground blurs below. Using momentum and pure strength, they swing themselves back onto the roof and continue running. 
Final shot: the train rockets into another tunnel while the courier clings to the front section.