Buffy tried to force herself to move -- to step away, to shift, to do something -- but she couldn't. The hold he had on her mind was too strong, and she had no control over her own body anymore. That was probably one of the most frightening situations to be in at that point.
The sides of her vision began to darken, and everything became fuzzy. Her head swam as Raidon slammed his fist into it over and over. It took a while longer than it would for most people, but eventually, the Slayer blacked out and went limp.