Oh... blast it all.

Percival winced to himself when his disarming spell went awry. Really, it was much easier to attack someone when they weren't armed. And then he was stumbling and landing on his back, taking a moment to suck the wind back into him. He would not be beaten by a boy who looked as if he were barely out of school himself, and certainly of no significance (it is safe to assume that Mr. Swinton was certainly not so educated as to be knowledgable of the distinguished pureblooded males of his era), and certainly not when he knew that the whole of the rest of his life hung by a thread before the hardly-stable cat that was the Dark Lord and his closest followers.

He did, however, manage to deflect the second curse from his position on the floor. Perhaps he wasn't entirely incompetant.

"Furnunculus!" he shouted pointing his wand at that little twerp of a boy. "Diffindo!" He cried soon after, hoping to cut something important. Like his wand arm off or something.