The Ticking Man.

In the remote west coast of Scotland, a drug dealer double-crosses and kills a drug trafficker who imports drugs for him. The dealer is arrested and learns that the murder was witnessed by a couple of anonymous locals. Facing life imprisonment, the dealer decides to hire a hitman to eliminate all the potential witnesses. Outside a rural police station, the hired hitman starts a stopwatch, runs across a road, jumps into his car, and takes off with a screech. He drives full speed through the barren country until he reaches the remote, one street hamlet of Bartoun. He checks his stopwatch. It reads 28 minutes, 36 seconds. He sees a poster advertising a fair in the next village. The residents of Bartoun are advised to meet on main street at noon to get a ride. As the people begin to congregate the next day, the hitman walks toward them and begins shooting. He knows that he has 28 minutes and 36 seconds before the police arrive.