As Buji walked conscientiously into the dungeon, he couldn't help but think about a few phenomenons. First, he thought about the key.
The key had been a result in form of reward he got after one of his two raids. He could call this key a rarity, since it belonged to a Dormant dungeon. And...Dormant dungeons are rarities too.
He had wondered why the orb had suddenly transformed into a key, but now he thought about it and its connection to the Dormant dungeon, he finalised that the key was no ordinary item.
And that should be the reason why the system had obliged him to make use of it only after he was able to unlock it. It also seemed like the spin wheel could have given him a different kind of Dormant dungeon if a different key had fallen to his luck.
'An entrance key to the Infernal Forge huh.'
Whether 'Infernal' or 'Internal', a raid is a raid, and a dungeon is a dungeon.