She's waving it around like an idiot in a shop full of people that aren't necessarily paying attention, and Klaus grabs her wrist to stop a particularly wide (and surprisingly well-executed) arc of the cutlass that might have cut into his midsection if he hadn't. "Careful with that, Miss Pond," he tells her, and lets her wrist go. "You might just end up hurting someone."

Not him, obviously, but someone.