Where Did They Go?

My husband, "Rob", told me this story.
He’s not one to believe in ghosts, but he cannot explain what happened this night.

He was the night shift manager of a fast food restaurant. Everyone had clocked out and left. He was there alone finishing paperwork. Everything was quiet, then he heard a knock. The knock was coming from the customer entrance door. Thinking it might be one of his friends, he got up to see who it was. The door was glass, so he could see a man with a little blond haired girl standing there. He didn’t know the man or the girl. He told them the restaurant was closed. The man said the little girl needed to use the bathroom. Rob let them in then locked the door behind them. While the man took the girl to the bathroom, Rob continued his paperwork. He couldn’t see them from his desk, so he yelled out, "are you done?" No one answered. He waited a couple more minutes then asked again. Still, no answer. He then got up and walked to the restroom to check on the man and the girl. No one was in the men’s or women’s restroom. He walked into the restaurant lobby thinking they may have sat down to rest. No one was there. He checked the work areas. No one was there. Rob was confused. He checked all the doors. They were still locked and only he had the keys. He went to the drive-thru window, unlocked and opened it. He stuck his head out and looked around the parking lot area. No one was there. He was alone. Just as he walked away from the drive-thru window, he heard a knock coming from it. He turned around and saw the little girl with the most terrifying look he had ever seen. She appeared to be "growling" at him and had her hands up in "claws". He said she looked like a devil child. Thinking it was his imagination, he closed his eyes and shook his head. When he opened his eyes again, she was gone. He ran to the drive-thru window and opened it again to look outside. No one was there. There was no way she could have left that fast out of the parking lot area. It was then he realized the man and little girl had to be ghosts. He said it really scared the heck out of him.

He waited a while that night before he left. He was too scared to leave. Where did they Go? Who was the man and girl? Where did they come from? How did they get out of the restaurant? Was it just a dream by an overworked fast food night manager that fell asleep while doing paperwork?
We may never know