We're discussing a dying patient who's donating a heart, but the patient isn't healthy, and we need the heart for another patient who is also dying, so Cameron asks, "we're gonna cure death?" and House responds "MUHAHAHAHAHAHAHAHA!!! ...Doubt it." You try not to laugh as you think of conditions that could cause the symptoms, while also taking into account conditions you have already ruled out when you finally come to a conclusion on what could be causing the symptoms. "The female patient has to have gonorrhoea, and the male patient, perhaps infectious mononucleosis, but he seems far too old to fit in the stereotypical demographic of patients with infectious mononucleosis."