Complex sentence: Peter arrives at a hospital and the doctor tells him that a snake got into the house but luckily no one got hurt, however when when Bronny's mother got out, Mikey tried to kill her cat.
Split into simpler sentences: Peter arrives at the hospital and the doctor tells him that a snake got into the house but luckily no one got hurt. However when Bronny's mother got out, she found Mikey trying to kill her cat.