If You're So Smart, Then Why Are You Dead? - S2-E7
Continuity mistake: When they are talking to the two kids outside of the school for the first time, one of the kids has a juice box. Shawn starts talking and it shows from behind the one kid with the juice box and he is about to take a sip, then the shot changes and the juice box is by his side.
If You're So Smart, Then Why Are You Dead? - S2-E7
Continuity mistake: When Shawn calls the first student up to the board to write a number, firstly the written number is 6.00214, which is an incorrect Avagadro's number, but it is not always this incorrect number. At some point during filming somebody changed it to the correct number: 6.02214, and you can see the number actually changing back and forth between the two numerous times during this scene.
If You're So Smart, Then Why Are You Dead? - S2-E7
Continuity mistake: At the beginning of the episode when Shawn and Gus are walking to their office, in some shots the tide is in, in others the tide is out.
Chosen answer: "Psych: The Musical" was supposed to air during the regular season 7 schedule, before Chief Vick is suspended and Jules discovers Shawn's lie, but the network decided to push it back to air as a special episode, sort of as a tie in with the holiday season and a lead in to season 8, which was to begin only a couple of months later.