At the L.A. Supernatural Convention in 2011, Jensen Ackles praised the performance of Christopher Heyerdahl (Alistair) in this episode, saying that during the torture scene Ackles was thinking "'Wow, I'm being totally out-acted here!' I mean, wasn't he good?" The audience replied with massive applause.
First time Dean called Castiel 'Cass' to his face.
The "Angel exorcism" incantation that Alastair used was: "Omnipotentis Dei potestatem invoco. Omnipotentis Dei potestatem invoco, Aborro te ut. Angelum omnium obsequendum domine expuet domine expuet deum adempiremus veritas." Which loosely translates to: "I invoke the power and authority of God. I invoke the power and authority of God. Worship Earth, this Angel in Your service, Lord reveal him, Lord reveal him!"
While Dean is torturing him, Alastair remarks, "It's your professionalism that I respect." This is the same line used in Little Shop of Horrors (1986),
spoken by the dental patient in response to the sadistic dentist who is trying to cause him pain. However, the dentist didn't know that the patient was a masochist who was enjoying what the dentist was doing. By referencing this, Alastair may have been trying to indicate that Dean's torture attempts were not having the desired result.
Alastair calls Dean "Grasshopper" - from Kung Fu (1972), where the Shaolin Master Po nicknamed his student "Grasshopper". This term has come to refer to one who is a novice or a student or disciple, as Dean had been to Alastair.