When the midnight hour was approaching and he still hadn't come home, Hermione knew she couldn't wait any longer. He might be gone for days or even weeks. It would be easier to go without a long, emotional goodbye. She was afraid that if she allowed him, he would talk her into staying. Leaving in the middle of the night before he could return was better. Maybe he would forgive her one day. She hoped so even if it would be better if he hated her until the day he died.