Wrapping long fingers around the mug, the Doctor shrugged, staring into the tea before he looked up at Jack. "I don't know," he admitted. "I don't know why this is different, maybe because she lived with us, she was family without any of that past heartache, and now she's another name on the wall. Maybe it's Nate still being here. Maybe it's the fact that she wore that dress on Mardi Gras, Jack, I don't know."