When the T-101 finally get his head and buddy bashed in by the T-1000; why is the camera eye sound so pronounced?

Throughout the entirety of the movie, you never hear it. Then after he gets bashed to the head, you hear a very pronounced adjustment of the camera eye on the T-101. Should we assume that while not exposed, the skull of the T-101 has sound proof insulation to not allow for such a robotic (cybernetic) sound?