Visible crew/equipment: If you look closely, after the shootings with the Russians and the guys go in to the second room, next to Chris Brown you can visibly see the camera man (shorts and the camera).
Other mistake: Paul Walker repeatedly looks through the scope as he is perched in sniper position with the lens cap still on.
Character mistake: When Detective Welles is searching for Naomi in the Police Computer System he types "Naomi, Cozier" which is backwards - he should have searched "Cozier, Naomi" or skipped the comma entirely. (00:58:20)
Continuity mistake: Paul Walker enters the van and closes the door. Then we can see that the driver's door is opened again and then a few seconds later closed again. (01:09:16)
Answer: They told a hostage to call a news station knowing that that station would send a chopper.