The body language is obvious. She starts off with her paw first, trying to turn him over. ‘Submit!’ this is the basic posture pups learn within the first two weeks of their lives.
Once the paws don’t work she starts using teeth. The pup hunkers down stubbornly. Then she gets rougher. But she never SHOOK him like a rat, which is what they do when hunting. If she wanted to really hurt him she could have broken its neck easily, crushed ribs, broken legs.