Complex sentence: They manage to escape with the bound volumes of records in a patrol car which was inadvertently left with the keys inside, and, after picking up Greenfield at the hospital, they make their way to a beach house belonging to relatives of Aggie's.
Split into simpler sentences: They manage to escape with the bound volumes of records, and get away in a patrol car which was inadvertently left with the keys inside. After picking up Greenfield at the hospital, they make their way to a beach house belonging to relatives of Aggie's.