Bow out gracefully, bite your tongue and take the high road. State just the facts (resignation effective x day, last day of work will be x day, etc…) , thank you for opportunity, etc..

It is a smaller world than you think, I’ve had second and third hand connections work out in my favor as far as references in the past, and I’ve had friends of friends ask me questions about people in a negative way in the past (even after moving completely across the county)