"Cmon, kiddo.." Arthur pleaded through the door to your bedroom, you were mad at him because he wouldnt get something off the shelf for you.

You had managed to reach the lock on the door so he was locked out, he had the key to the lock so he really wasnt locked out.

"It aint makin' a difference, youre comin' out later for dinner anyway." He added with a chuckle, knowing youd come out for dinner.

it didnt make sense to him why you were locking yourself in your room over something on the shelf.