The Heartwood man was born to sin, set him free and he will be a sinner

Ultimately, it would be his inexperience that cost him. The man was on his back and reached for an area that was not vulnerable upon her as she, on all fours, was well and able to protect. Her parted jowls protected the swanlike throat she was certain he wished to grip and crush, and his fangs met the bridge of her muzzle. She was not able to avoid his fangs completely, and as he thrashed Hydra willfully ignored him as she adjusted her position to strike at his own throat. Snapping jaws be damned, she would do to him as he had done to Rannoch—she cared not what he did to the rest of the wilds, but he would not touch what was hers. There was little passion to her movements, but it was expert and precise; she knew what she was doing, she had done it too many times before... only, more. 

You see, technically, Rannoch was no longer hers. His union with Liffey meant that. Liffey could avenge Rannoch. Hydra was only protecting her mountain and what lay beyond it. She did not think she needed to kill Vaati anymore to accomplish that. Only strike him down, and have him see that she was in charge here. That she was passionate about, and if he thought to struggle more, she might very well kill him then. If she were able to reach his throat at all, he would come to realize quickly enough she did not seek to seize it—only to tear and savage. 

He might even feel as Rannoch had that day, if she succeeded. But Hydra would not go so far as that; she did not want him to lose so much blood as to pass out. No, she would need him awake.