You are Harsha, a mighty warrior. After a long bout of drinking last week, you learned of the legendary Goblin Gauntlet, an underground labyrinth once used to train elite forces for the goblin armies in the Mine Wars. It has been long abandoned and there may be great riches stored inside, but no one has yet survived to retrieve them. Drunk Harsha was confident that he would be the first. Now you, Sober Harsha, must live up to your past self's boasts. You have located the entrance in the old goblin-clan caves, and now stand before a carven image of a scarred and grinning goblin face staring back at you from the thick stone door. 

I make a rude face at the goblin and waggle my fingers in my ears, then give the door a good shove.

The door is airtight but unlocked. The door opens outward, not inward. 

(The Player does not know the door opens outward. To avoid confusion, there should be some visual sign that it does.)

The door does not budge. 

Two teeth on the carved goblin-head jut out from the door, almost like handles. 

I give the door a good shove, then get a crowbar out of my pack and begin trying to lever the door apart from the centre.

The door is thick enough to be difficult to damage with brute force. It will take some time to force it open this way, but the efforts will break the airtight seal. The other side of the door is at slightly lower pressure than the caves. Air will flow in. 

[Harsha has a crowbar.]

The door grinds and crunches slightly. A small crack opens where it meets the floor. You hear a faint whistle. 

The mechanism to reset the dungeon completes its final steps when it senses a change in air pressure. The dungeon is setting up for a new group of goblins.