Complex sentence: Johnny makes use of a crane to capture Oscar from the moving boat, who is then arrested and the diamonds are returned, but the effort drains Johnny's remaining power reserves, causing Ben to frantically use a defibrillator in an effort to save Johnny.
Split into simpler sentences: Johnny makes use of a crane to capture Oscar from the moving boat. Oscar is arrested and the diamonds are returned, but the effort drains Johnny's remaining power reserves, causing Ben to frantically use a defibrillator in an effort to save Johnny.