"Sadistic, me?" Watson isn't quite sure whether he ought to laugh at that or not. "No, no. I am a physician. If I cause pain, it's because the good it will do outweighs it. Hippocratic oath and all that."

He says this and also looks at Cerrit, because he has a notion of how that statement might be taken, but also he very much needs to see how it is actually taken.