Monday evening, Dad was in such a scenario. He was coming home from work and the door was locked.
His attempt to open the door summoned Tony. Tony said, from the inside, "Daddy! I am coming!" Daddy thought how nice to was to hear Tony using the phrase. He was learning more and more. How wonderful!
Tony opened the door. Mom then told Dad what Tony had done. Tony was standing at the door when he told Dad he was coming; and then waited a moment before he opened the door. So Tony wasn't using the words in the right way.
He will learn eventually, reasoned a deflated Dad.