"My theory is this: Kate told Toby it was her fault her father died. What if they were all watching the Steelers game (sans Kevin), and somehow a fire started in the house. Maybe the family all gets out at first, except the dog. Since Kate seems to have an attachment to the dog, she freaks out about it, and Jack runs back in to find the pup. Dog gets out, Jack doesn’t. Or, if he does, he’s not in good shape and ends up dying in the hospital."