Consider the following hypothetical:
The 5-person party is in the Engineering District, fleeing a detachment of 12 Goblin Points (Lightly-armored Despot skirmishers) and two Goblin Scuta (Points with swords instead of spears, specialize in creating openings for other Scuta to slip in and swing). They slip into a warehouse through one of the broad double-doors, which is hanging off of its top hinge. They don't stop to consider whether the massive wooden door was ripped from its hinge during the riots following the bells, or by something inside the warehouse getting out. The party does not care about these things, because the goblins chasing them attacked immediately after a much larger battle with four Savage Elementalists and their flaming-rock minions.
The players are weary, wounded, and out of encounter attack powers and second winds. With mere moments before the goblins arrive, the players manage to hoist the door back up. Two characters hold the door fast in its frame, another player braces the first two so they won't slide once the goblins start slamming into it, and the last player, a swordmage with ritual caster, begins incanting the Arcane Lock ritual...after some clever rules-laywering where he points out that the ritual description does not require a functional door, and causes anyone other than the caster to experience the door in question as "locked." Amused by the creativity, and enjoying the tense scenario, the DM allows this.
The players are now locked in a skill challenge.
