Complex sentence: Schaeffer advises Book to keep the case secret so they can work out how to move forward with it, however when Book returns home, he is ambushed by McFee in a parking garage, nearly killed, badly wounded.
Split into simpler sentences: Schaeffer advises Book to keep the case secret so they can work out how to move forward with it. However as Book returns home, he is ambushed by McFee in a parking garage, and he is badly wounded.