This cat probably overestimates the capabilities of its paws and feels that a single swipe can actually result in the dog's throat getting slit. It probably worked on some tiny little cretin and gave the cat lots of confidence. It now believes that the same can be done to this dog which is covered by thick fur.
The cat believes that it has held the dog hostage. The dog doesn't know its own strength and probably saw what the cat had done to the fly, it fears the same happening to his neck. Its heart rate has began to flutter rapidly and the only reaction of the dog is to stare at the owner in pure fear. The cat demands ransom in exchange for the dog's life. "Get me my food or the dog gets it", "Get me my bed or the dog gets it". Works every time.