Garion is a simple boy. Thus, he doesn't do anything all that odd with the internal organs of the man. His job was to stop the words, to stop the magic so that Ray could take care of things.

The easiest way to do that, however, is to knock someone out. So, hawling back good and hard, he knocks the man across the jaw with everything he has.

In the future, Garion would knock a Grolim out with enough force to nearly kill him. He's younger, less experienced, and slightly less pissed off than he will be then, thus it's not as effective.

But it's still a damn good hit.