House's customary red and gray plush tennis ball is all red in this episode. (House may have multiple similar toys. In "Informed Consent" (#3.3) the ball is red and purple.)
Clarence's gold tooth is shiny in some scenes but clearly wearing off in others.
Clarence is walked out of the hospital at the end. Prisoner or no, he would still be required to leave the building in a wheelchair.
When Cameron shows House her clinic patient's file, he tells her the patient has "metastatic squamous cell lung cancer. Six months, tops." Cameron asks if he's seen the x-ray and he states he was just guessing. No biopsy has been done, so the type of cancer cannot be determined with certainty. Later views of the x-ray clearly show lung cancer with metastases: with experience, doctors can come to view a disease pattern as "consistent with," but absent a biopsy, there is no true diagnosis. Cameron does eventually do a biopsy, unlike "Babies and Bathwater," where small cell lung cancer was diagnosed without one.
Cameron calls the Kubler-Ross stages of grief "the five stages of dying".
When Clarence is getting the spinal tap, his nasal cannula is not in his nose, but off to the side.
When Dr. Cameron goes to Dr. Wilson for the Chest X ray consult, he's holding the x-ray film upside down.
When House examines Clarence in the dispensary, he places his stethoscope in backwards. They should angle toward the front of his head, not the back.