About the keystone:
I was doing my hair thus thinking mirror and something popped up in my head: if you want to spy you first need someone to spy on. If you don't have someone to spy on (and control) you can't spy/control. So, maybe we are the keystone to (((them))).
Q keeps telling us that we must unite and work together because it would put an end to their power. In their game of power and control WE are the necessity to make it happen.
What if WE (The People) are the keystone?