At the end, Arthur wonders if Merlin is wise or foolish and Merlin clumsily kicks over a pot of some liquid. In the days before indoor plumbing folks kept chamber pots beside or under the bed. The pot was used as a toilet during the night and the next day it was emptied into the outhouse. The liquid that Merlin splashed all over Arthur's room was stale urine.
Janet Montgomery (Princess Mithian) and Angel Coulby have both appeared in the TV mini-series Dancing on the Edge (2013). They played Sarah and Jessie respectively. Also starring in the show were Anthony Head (Uther Pendragon) and Sam Troughton, who is the cousin of actor Harry Melling who played Gilli in The Sorcerer's Shadow (2010).