This clever win condition relies on Spy Kit's unique property of granting an equipped creature every nonlegendary creature name in the game, which conveniently extends to other card types when combined with Central Elevator // Promising Stairs. By using Zur, Eternal Schemer's ability to turn Central Elevator // Promising Stairs into an enchantment creature with a base power and toughness equal to its mana value, you prepare the target for its transformation. Once Spy Kit is attached to the newly animated Central Elevator // Promising Stairs, the game treats that single permanent as possessing eight or more different names among unlocked doors of Rooms you control, instantly satisfying its upkeep trigger and winning you the game.