Continuity mistake: When Keith Palmer and Carl Webb meet they stop walking around to talk. When we see Carl's face, the sun is coming from behind him, the light shimmers through his hair and the light reflects on Keith's face. Than it cuts to a view from behind Carl, and there is suddenly no light, both stand in the shadow. (00:34:00)
Continuity mistake: Elizabeth walks away from the security brief and puts her arm on the wall. When David approaches her, her arm is still on the wall. When the camera changes to the front angle, her arm is not on the wall any more. This is an instant cut. (00:06:30)
Chosen answer: Nobody knew, not even the writers, until at least halfway through the season when they were writing the end. They wanted to keep all options open.
Nick N.