Let him know through training that his actions are to be held accountable. Do you do any formal training with him?
Young dogs do like structure, rules and routine, it builds their confidence when they have handlers that do control their being. Freedom comes earned. Dogs that feel the need to control their world lack confidence when they are so young they can'd deal with all that decision making.
If he decides that rushing out the door is necessary, he needs to know you let him do it, it wasn't his 'choice' Otherwise don't allow him the freedom to make such decisions. Set him up to succeed.