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)
Answer: According to Jack in season 5, Nina was "deep cover" before the pair ever met, so it's safe to assume she was recruited before she joined CTU. As for what her primary mission was, who knows? Perhaps it was to gather sensitive intel and pass it on to her superiors. Given that she worked for an intelligence agency, it's not a stretch. Or perhaps we may find out in season seven.
Cubs Fan ★