When we first enter the Black Armoury and meet Ada she tells us that this place is not meant for Guardians. Now hold on just a damn second, if the Black Armoury is not meant to be visited by guardians, then why the frick is it located in the -blam!-ing tower, literally the place where guardians gather. Secondly, how the -blam!- does a golden age armory exist in the -blam!-ing tower, and we guardians, you know, the ones who own the the tower, not know about this? Like it's literally located a 2 min walk away from the Vanguard Commanders.... How the hell does Spider know about this place in the tower and we don't? How?......
Honestly I have the same question too . So, after Red War we moved to this new place to start everything. The doors are already there, locked and no one know whats behind until now. The Vanguards and Guardians have occupied a place where they don't have much idea. Our "friend" Spider knows it for...I believe it has longer than we could believe . A guy, named himself Drifter is there hosting the gambit thing who we have very limited information about him. In that case, I would say, No one in this Tower can re-gain my trust.