"Back-up plan." The Master shrugged. "Though I suppose that does mean the Doctor hasn't yet told you I'm not so dead after all. How rude." He smirked. "And yet, so very much the Doctor. But you already know that, and you still are his loyal and faithful friend. That always has rather amazed me." He tilted his head. "How is it that the Doctor can treat you so shabbily and still keep your loyalty?"