George had been staring into the featureless depths of her oatmeal when she heard a voice. She started to speak before saw who it was, "Huh? --Oh...."
George was not a particularly good liar, especially under pressure. Her usual tactics generally included sarcasm and not caring. So with her initial reaction, she didn't mean to look like someone who'd just been busted, someone caught in the middle of a lie. She was both those things, but he didn't need to know that.
"Hi."
George decided not to correct him. She liked that name Millie but the less he knew the better. She stared at him, unsure of how to proceed or socially interact. How well did he know her as George? Was she already giving herself away? Quick! How would George -not- act? Suddenly an image of being overly bubbly and social in a Deloris Herbig impersonation came to mind, but the image was too scarring to act upon.