Erika Swyler said this quote

The problem with stealing the magician's assistant from a carnival was that you were always waiting for her to disappear. He expected her to vanish. She had in fact, multiple times, before Simon was born, and just after, too. ...Daniel wanted to be worried for, wanted to be missed without doing any of the leaving that missing demanded. When Paulina left, he counted breaths, and thought constantly of the disappearing box. The reappearing was the most important part of the trick. Eventually he stopped living in fear that she wouldn't come back. The more pressing concern was that she was cutting herself in two.