Joel Grey, the actor who plays Ezra Powell, played the Wizard of Oz in the Broadway show "Wicked". As Dr. House examines Powell behind a blanket, House says "Pay no attention to the man behind the curtain", a quote from The Wizard of Oz (1939).
The wall clock in the MRI room is labeled 'Stoia Tucker', which is also the pharmaceutical company in House M.D.: TB or Not TB (2005) (Most likely from Chris Stoia, first assistant director on the show.)
House: Don't go towards the light. Referencing the movie Poltergeist (1982) and its sequels, where the main character Carol Anne is told not to "go into the light." Associated with the "white light" reported in many near-death experiences.
Joel Grey, who plays Ezra Powell, is playing a doctor with cancer who asks a team of physicians to help him die. He plays a character almost identical to this on Private Practice: Nothing to Fear (2009), where he plays a doctor with cancer and in unbearable pain who begs his two physician friends help him kill himself.