Why does Victor feels his family will be safer if he leaves Switzerland?

Victor believes his family will be safer if he leaves Switzerland because he feels responsible for the tragic consequences of his creation, the creature. He fears that the creature's anger and desire for revenge could endanger his loved ones. By distancing himself from his family, Victor hopes to protect them from the creature's wrath and prevent further tragedy. Ultimately, his decision stems from guilt and a desire to shield those he cares about from the chaos he has unleashed.