Complex sentence: Alerted by Commissioner Gordon, Batman races out to the school; an immediate assembly is made by the school's student leaders: including Richard "Dick" Grayson, Pete, and Susie, the school's head cheerleader.
Split into simpler sentences: Alerted by Commissioner Gordon, Batman races out to the school. An immediate assembly is made by the school's student leaders: including Richard "Dick" Grayson, Pete, and Susie, the school's head cheerleader.