Guild Wars 2

… when you have beaten story mode with one of your characters?

I am asking because, I think this would be kind of a clever mechanic. Since once you have done story mode you probably want to skip right to explorable because story mode has nothing by isself to offer, execpt for the story, which you already know…

Clear the Story mode of the dungeon will grant you the permission to start the explorable mode. You can join another explorable mode dungeon that opened by your group members. You just cannot open yourself.