It took a lot to surprise Pandora, and yet the boy managed to do just that. She should have paid more attention, but she had simply gloried so much in the torture that she'd forgotten how some were capable of great feats under the right circumstances.
One moment she was glorying in the boy's pain, and the next she was lying flat on the floor, her head having hit first the bed frame then the glass covered floor, and her vision playing havoc with her. She defensively shot out a stunning spell at random, unable to see or even think straight, but nevertheles nowhere near defenseless.