During this episode, Laura Heathridge's left arm is missing and she wears a prosthetic limb. At the end of the episode, she opens the door to a mystery man using a real left hand (not seemingly part of her delusion), then also reaches to the man using a real left hand. It could be argued that her real left hand is part of her delusion, but if this is the case then she should have had a real arm from the moment the doorbell rang (presumably also part of her delusion).
Reid mentions the drowning test to discover if someone is a witch was used during the Salem witch trials. That is incorrect. There were never any kind of tests performed on supposed witches in the infamous 1692 trials; they were convicted based only on accusations and spectral evidence.
Hotchner: "All that we see or seem is but a dream within a dream." Edgar Allan Poe
Prentiss: "We are each our own devil, and we make this world our own hell." Oscar Wilde
The song heard at the end of this episode was "Smoke Gets in Your Eyes" by The Platters.
This episode was directed by series star Matthew Gray Gubler.