"Throwing down the gauntlet" is a term from the medieval practice of issuing a challenge by removing the gauntlet and throwing it at the feet of the other person.
Many of the episode titles are also the names or opening lines of songs; "throwing down the gauntlet" is the majority of the opening line of "Blood In, Blood Out" by Exodus.
Mark Hildreth (who plays Tom MacGregor Jr.) and Maite Schwartz (who plays Celia Jaffe) both appear in this episode yet share no screen time. Coincidentally, both also appear in the same episode of the CW's Supernatural in season four episode fourteen entitled 'Sex and Violence'. Hildreth plays Adam Benson while Schwartz plays Dr. Cara Roberts.
Jane's middle name is Clementine, according to Sister Winifred Callahan.