The use of her powers doesn't even cross her decaying mind at that point, since she is drawing near the now-downed target. There would be gratitude for making the process easier, were gratitude something that she could still comprehend.

Instead, her body acts on its own. As if she knew what to do all along. Once she is close enough to the body, she crumples to the ground beside it, face first, teeth sinking into flesh...