Complex sentence: When the Gogans arrive in town and demand Pete back, Nora refuses to hand him over and, as the Gogans attempt to chase them in a small boat, Elliot "torpedoes" their boat, saving Pete.
Split into simpler sentences: When the Gogans arrive in town and demand Pete back, Nora refuses to hand him over. As the Gogans attempt to chase them in a small boat, Elliot "torpedoes" their boat, saving Pete.