Just as Fearless said, Hidden Lurker was an extremely selfish person. The Atlanta's Key was the special reward after the United Alliance completed an extremely large scale quest. As the team leader, Hidden Lurker easily pocketed it. If he attracted attention to this, he would be condemned by everyone.
However, as someone in the know, Hidden Lurker had spent much money to ask about the Atlanta's Key storyline and looked through many books in the library.
Berserk Thunder City and Dead Spirit Swamp were both on the original location of Atlanta so they had more records. Hidden Lurker understood the true value of the key more than Quan Zhen Sect.
If his subordinates had the ability, Hidden Lurker did not have to wait to take action as the quest was in the territory of the Dark Faction.