KingZayd wrote...
Why does the Catalyst (of whom the Citadel is part of) need a reaper that it controls to stay behind and tell it when the Harvest is ready [the organic races are on the Citadel (part of the Catalyst)], so that it can send a signal to the Keepers so that they can open the Citadel relay (part of the Catalyst)? How do the Protheans sneak onto the Citadel (part of the Catalyst) and change it without alerting the Catalyst? When the Citadel receives Sovereign's signal, and the keepers aren't activated, why doesn't it let Sovereign know what's going on? Why does Sovereign have to spend thousands of years figuring out by himself, and eventually using Saren to discover the truth. Why does the Citadel (part of the catalyst) have a master control console that organics can use? Why hasn't the Catalyst made the other reapers it controls who can enter the Milky Way using FTL drives, do so in all that time?
You're making several assumptions:
A) You assume "control" means 100% active, every action control.

You assume the Catalyst is active and monitoring the Citadel.
C) You assume the Catalyst is in control of the Citadel.
D) You assume the Catalyst can doing anything beyond what is shown when the Crucible is attached.