As Wilson explains to House why he won't agree to conventional therapy for his thymoma, he starts going through some of the gifts that his patients have given him. He starts picking the gifts from the deceased patients who had a good chance to survive with conventional therapy, but died anyway. He picks up a robot toy and starts talking about John, an 8 year old boy who had a cancer with a 92% survival rate, but died anyway.
Later, as Wilson undergoes radical chemotherapy himself, he starts hallucinating. He sees an 8 year old boy in front of him, who asks if Wilson remembers him, but Wilson can't until the boy tells him he's John Taylor. John starts asking Wilson why he died, but Wilson breaks down and starts sobbing. House soon returns and realizes what's wrong and starts assuring Wilson it was only a hallucination.