Complex sentence: Ben, Carter, and Denise use Ben's car to flee from an entire flock of zombies and goes to the police station to discover that the town has been evacuated, before they are chased by the zombie horde into a holding cell.
Split into simpler sentences: Ben, Carter, and Denise use Ben's car to flee from an entire flock of zombies. They take refuge in the police station and discover that the town has been evacuated, before they are chased by the zombie horde into a holding cell.