She was sprinting across the floor by the time Sam fell, the thing grabbing him by the neck. She wasn't worried, she would get there in time but Sam in danger was never a good thing in her book.
The one with the fangs bared turned to dust moments after he started lowering his neck to bite Sam, the wooden stake the demon carried having embedded in his heart.
The other vampire jumped down from the wood and lunged at her eyes feral and wild, but obviously not expecting her strength. And not expecting her own eyes to shift to demonic black. He hesitated just for a moment, long enough for Ruby to nod to Sam to finish him off.