Your 2-year-old is in the bedroom bawling, you're out in the hall, and there's a locked door between you. On the door's knob or on the plate around it, there should be a small hole that's made just for this situation. Take a slim piece of metal, such as a small flathead screwdriver, and slip it in the hole. Compress the spring inside or slip the screwdriver head into the slot on the spring and turn. Door unlocked, toddler safe, shoulder not broken.