Complex sentence: Batman hurls himself and Grayson into a miles-deep crevasse filled with lava and blows up the entire cave, igniting an underground volcano and destroying everything--only to be saved by Superman at the last minute and brought to Carrie in the Batmobile.
Split into simpler sentences: Batman hurls himself and Grayson into a miles-deep crevasse filled with lava and blows up the entire cave, igniting an underground volcano and destroying everything. He is saved by Superman at the last minute and brought to Carrie in the Batmobile.