OK, you know how the clock is set at a certain time to make the Mouse Maker work when it goes off? Well, Luke never told his Grandmother this. But if you read it very carefully, when the Grandma and Luke are witnessing the witches being turned into mice, the Grandma says something like, "It must be the clocks that are being set off to make the mouse maker work." Now, if you remember, Luke never DID tell his grandmother this. Pretty bad.