Continuity mistake: The 10/6's on the Mad Hatter's mind control cards come and go throughout the episode.
Continuity mistake: The 10/6th on the Mad Hatter's mind control cards come and go throughout the episode. An example is when he first is shown holding them they're blank. Then when he decides to use them on his date with Alice they've suddenly got the 10/6th.
Continuity mistake: When Jervis Tetch is shown he's around 5'5 maybe with blue eyes and sandy white looking hair. Yet the day after his night out with Alice he's suddenly around Bruce Wayne's size with blond hair and his eyes are no longer blue.
Answer: She escaped off-screen and created a copy of herself to fool everyone.