Complex sentence: As the song begins to reach its climax, Perry is shown to be on fire and is hit by a car, as thousands of tiny broken debris from the car shatter behind her, and in a simultaneous scene the shattered car remnants are replaced with flowers.
Split into simpler sentences: As the song begins to reach its climax, Perry is shown to be on fire. A car crashes behind her as thousands of tiny broken debris from the car shatter behind her, and in a simultaneous scene the shattered car remnants are replaced with flowers.