Bellatrix had noted the meekness had left her prey and tried to return her knife to Hermione's throat but she was too slow. Letting out a war cry fuelled by anger and shame at having allowed this woman to touch her like that Hermione grabbed the dark witch. She dug her nails into her arms using all her remaining strength to roll over with her so that she was now on top. The struggle was fierce Bellatrix may have looked sickly, skinny, and weak but she was fiercely strong.