Continuity mistake: In Episode 15 (Day 1), the pregnancy test that Teri takes to the bathroom is a "TrueBlue" (close up shot on it), but the one that Kim finds there is a "ClearBlue". (00:13:07 - 00:19:57)
Continuity mistake: At one point during Alberta Green's debrief of Jack, the shot changes to a split screen. In the left box, Jack stands up from the table before he does in the right box. (00:04:05)
Continuity mistake: When entering the safe-house Nina walks past the lit lamp on a side table. Seconds later when Mrs. Bauer walks past, it is switched off. (00:11:15)
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 ★