And to complete S2, L4, let's also look at "Snakeskin Boots of Billy the Kid."
Guards Encountered: Crypt, Laser Light Room
Number of Unencountered Guards: 1
Rooms not Entered: Observatory, Medusa's Lair, King's Storeroom, Secret Password, Ledges
Notes: Most people eliminated the Ledges as an option because there was a guard in the other entrance room. Since the only room that opened from the Pit was the Laser Light Room, and it didn't appear that the door opened to Medusa's Lair, the only unlocked room left would have been the Room of the Secret Password.
My Thoughts: The first thing I'd like to mention about this run is that I find the guard in the Laser Light Room to be very peculiar. When Kelly first enters the room, the camera angle is different from normal and the room seems unusually foggier than normal. Additionally, the guard came around from the other side of the wall, rather than waiting perched directly to the side of the wall. He seemed to also come out from hiding after a much longer delay than usual. Overall, I find the Laser Light Room guard out of place. Perhaps he was originally not supposed to be stationed there, but then was moved for some reason at the start of the run, and was not ready to come out when Kelly entered the room?
Okay, enough of my hogwash. Let's move on to finding the unencountered guard.
-- Medusa's Lair most certainly did not open from the Laser Light Room, nor did the Jesters' Court give access to the King's Storeroom. There were no lighting changes to indicate those doors opened.
-- Since there was already a guard in the Crypt, I don't see why there would have been a need to station a guard in the Ledges as well.
-- This only leaves the Room of the Secret Password, which makes sense. In addition to probably holding a guard two episodes earlier ("Golden Goblet of Attila the Hun"), stationing a guard there would have punished the team for not trying the door from the Mineshaft to the Shrine. The guard would have also been one room away from the artifact. Since the elevator was down in the Mineshaft in this run, and there were a number of episodes where teams bypassed the chance to try the ladder but instead going straight to the elevator (i.e. "Leopard-Skin Cloak of Annie Oakley," "Two-Cornered Hat of Napoleon," and "Very Tall Turban of Ahmed Baba"), it would not be out of the question.