When I first ran it, one of my players had the brilliant idea to try to scale the outside of the tower. *Internal screaming* I let him, and he eventually found one of the vents, which he NATURALLY wanted to climb inside. Even after an ambiguous warning, and telling him he'd have to drop his shield and pack to fit, he insisted on trying to shimmy through the Wizard vent...
And that's the story of how a player died even before the party entered the tower. It was glorious.