Complex sentence: The fire extinguisher he had been carrying smashed into Pryce's head, before striking the Shadow's roll hoop, tearing it away from the car so hard that it was thrown up and over the adjacent grandstand.
Split into simpler sentences: The fire extinguisher he had been carrying smashed into Pryce's head, before striking the Shadow's roll hoop. The force of the impact was such that the extinguisher was thrown up and over the adjacent grandstand.