By the time Dean realizes his mistake, Castiel's fingers have closed around his arm like a vise, and nausea floods his system on the heels of pain. He jerks back, manages to absorb most of the punch that follows with his cheek, but it's still enough to addle him.

"Cas," he tries again, spitting blood as he scrambles along the edge of the counter that's trapped him and into the open room. "Cas, please. It's Dean. I know you don't want to hurt me."

It worked last time. It can work again. Dean feels the sword dangling at his back, and he pulls it forward with his good arm, holds it like a plea as much as a defense. "Please don't."