Hearing students actually suggest that he duel Professor Snape again, the muscles in Professor Lockhart's face began to twitch involuntarily, and he said dryly, "The demonstration is over!"
How to defend against the Disarming Charm?
Professor Lockhart naturally knew, but he had no confidence in using a Shield Charm to block Professor Snape's Disarming Charm, let alone beating him to the punch by interrupting his incantation beforehand.
Chapter 530