Nap time still needs baby gate

Today E went down for his nap, around 3:30 like his usual time is. However, instead of putting up the baby gate the door was shut. Trying to encourage him to stay in his room even when it is nap time. E comes running out of the room, stops dead in his tracks when he sees us, and then goes running back to his room. Most days it is hard not to laugh because he is just so cute, but I know the laughing encourages the behavior we are trying to break.