A wizard opened one of the fourth-floor bedroom doors and ran out into the corridor. His expression, when he saw the four Gryffindors in orange HazMat suits, was one of surprise. Even as the Death Eater faced the foursome and he raised his wand, he was coughing nonstop. Harry hit the wizard with a wandless, wordless Tripping Hex—which put the bloke flat on his back, on the corridor carpet. In ordinary circumstances, this would be only an annoyance for this Death Eater.