Master the Doorway

Doors are where back pays for itself, so make it a rule: the door doesn't open until the dog backs up.

Front door, car door, crate door — same script every time. Cue "back," wait for the space, then open. A dog moving away from the gap simply cannot bolt through it.

After a few weeks the door itself becomes the cue. Your dog sees your hand reach for the handle and backs up on their own, no word required.