Complex sentence: The fourth caution of the race flew on lap 99 when Kurt Busch, exiting turn 4, got loose and spun down the track, through the grass, and came to a stop a few yards from the start/finish line.
Split into simpler sentences: The fourth caution of the race flew on lap 99 for a single car spin on the front stretch. Exiting turn 4, Kurt Busch got loose and spun down the track, through the grass, and came to a stop a few yards from the start/finish line.