Day 4: 7:00 P.M.-8:00 P.M. - S4-E13
Character mistake: Near the start of the episode, Curtis asks how many square miles are affected by the blackout, and is told "approximately 8." A few minutes later, Sarah states that the blackout area is "everything within an 8 mile radius." These are vastly different amounts. An 8 mile radius would cover approximately 201 square miles. (00:02:25 - 00:06:55)
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.