Continuity mistake: When Jack is outside Dunlop Plaza, talking to Nina on the phone, he says, "Nina, it's Jack." But the transcript Tony looks at a few seconds later reads, "Nina, it's me, Jack." (00:17:15 - 00:18:00)
Continuity mistake: Shortly after the clock display reads 01:44, the time is shown again... and it's 01:42. (00:29:20 - 00:30:25)
Continuity mistake: When Richard is shot and on the floor, there is a blood blob above his shirt pocket that keeps disappearing and reappearing. (00:35:10)
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 ★