User blog comment:RayShepp654/How to defeat the Reapers Theories/@comment-1221773-20101031021231/@comment-1221773-20101031054102

Spart, if the Reapers control the space around the Citadel, they can wipe the Citadel clean of life. They've done it in previous purges, there's no reason they wouldn't do it this time.

And if getting to the manual controls is such a big deal, I'm sure the Reapers have other ways to gain control (ways which logically aren't as easy or quick to implement). They did build the Citadel.