What part of that is un-Paladinly?
Killing someone? Obviously not. That's what most Paladins dedicate their lives to.
Summoning them to a locked room? How is that different from shield bashing them so they can't move? Or attacking them in a norecall area? All you're doing is using the terrain to your advantage.
There's nothing that says a Paladin has to let their foe escape. Their goal is to kill them. By killing them in a locked room, you could even say that they are protecting innocent bystanders from getting caught in the crossfire.
