Visible crew/equipment: When Nina's just been shot, and makes it to the barn to call CTU (around 7.10am), while she's speaking on the phone there's a cameraman visible on the right hand side (DVD). (00:12:40)
Continuity mistake: When Jack stops at the bus station to get a bag, we see a shot of Jack's car from the point of view of the guy who has the bag. You can see a quite big camera inside the car on the left side. When we see the reverse shot from inside of the car, the camera is gone. (00:05:55)
Visible crew/equipment: Teri attacks Rick - the camera pans behind a pillar and the camera shadow can be seen on it. (00:20:35)
Visible crew/equipment: When we see Nina at the start (in the split screens) watch the bottom window and you will see a panning shot that swaps from her left side to her right. In this shot you can see the camera shadow across her back. (00:01:50)
Revealing mistake: Tony Almeida tries to phone with a telephone, which is not switched on. You see that the screen isn't displaying any information. (00:25:10)
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 ★