The final clip in this sketch shows the doctor explaining the treatment to the patient. Mr Wilson (patient) is clearly upset that it took so long to get to the root of the problem. The doctor clearly states that he only ever prescribed on the basis of the symptoms that Mr Wilson described to him.
'Turns out' means 'the result' "It turns out I've got cancer of the bowel!" The result is that the patient has cancer of the bowel.
Mr Wilson sarcastically thanks the doctor by saying: "Thanks a million!" This phrase is usually used when thanking someone greatly for something done.
The clip ends with the doctor telling the patient that he can continue to live a normal life and that nobody need know a thing (his condition won’t be obvious to other people) unless he chooses to tell them.