"He's a perfect anaesthetic," pipes up Elspeth. Of course, explaining this is part of her job. "But maybe a little too perfect. No one has any senses while they're under, and from the moment you start turning you can't sleep either. So me and another witch who can do visual illusions take turns piping movies at them while there's a batch changing. It's no one's favorite three days, but it's not torture anymore."