I assume this used to be a poll. I'll throw my name in the bin and go with something no one has said yet: The Marble Armrest of Xerxes. This one was just brutal. The girl entered both the Crypt and the Ledges with no guards popping out (she could've pulled all the books, but she just went with first one which opened the Ledges). A guard appeared in the Tomb of the Headless Kings and then the Quicksand Bog where she was taken out (there was no key in the Dark Forest, so she had to plow through the wall). Then her partner went through and tried the Bog-Shrine door and that didn't open. Then he had even more problems with the slide. It's like the slide was purposely slicker than before (previous run was Zac Turney's run). If the production crew felt like major assholes that day, they would've made the boy go up into the King's Storeroom via Room of the Ancient Warriors, thus forcing this team to go through EVERY room in the temple. However, that wouldn't have happened because the boy never got the other half pendant hanging on a button in the Jester's Court. He would've been taken out of the temple unless both the King's Storeroom and the Chamber of the Sacred Markers opened with the guard being in the upper room.
Yeah, Hans Holbein is very tough too, but the kid went down the slide, not up it. I rank that one third right behind Ivan the Terrible (second because of guard placements) and Xerxes (first).