To me, this question suggests a radical failure to understand the tiers of play in 4e D&D, and how these relate to the action resolution system.
From the PHB (pp 28-29; there is similar text in the DMG, p 146):
In the paragon tier, your character is a shining example of heroism, set well apart from the masses. Your class still largely determines your capabilities. In addition, you gain extra abilities in your specialty: your paragon path. When you reach 11th level, you choose a path of specialization, a course that defines who you are within a certain narrow range of criteria. You are able to travel more quickly from place to place, perhaps on a hippogriff mount or using a spell to grant your party flight. In combat, you might fly or even teleport short distances. Death becomes a surmountable obstacle, and the fate of a nation or even the world might hang in the balance as you undertake momentous quests. You navigate uncharted regions and explore long-forgotten dungeons, where you can expect to fight sneaky drow, savage giants, ferocious hydras, fearless golems, rampaging barbarian hordes, bloodthirsty vampires, and crafty mind flayers. When you face a dragon, it is a powerful adult who has established a lair and found its place in the world.
There is no such thing as a "paragon city" that uses ladders that are an obstacle to anyone. There are cities of drow and mind flayers: in AD&D these NPCs frequently relied on levitation, in 4e not so much, but I still don't think climbing ladders is going to be a big thing in one of these cities. Drow locks can be expected to be Lolth/web-inspired puzzles, while mind flayer locks would (I imagine) be psionic devices of some sort.