Day 4: 9:00 P.M.-10:00 P.M. - S4-E15
Plot hole: Dina Araz was executed at 8:57pmin the previous episode. At 9:01pm during this episode, the terrorists have already placed her body in the van, driven off with it, and abandoned it. Then someone had found the body, reported it in, and the information gotten to CTU. All in the course of four minutes. That is impossible, no matter how fast the terrorists were.
Day 4: 9:00 P.M.-10:00 P.M. - S4-E15
Factual error: The bad guy uses the thumb to access the Air Force base at the end of the episode. Thumb scanners are activated by the pulse and wouldn't work otherwise.
Day 4: 9:00 P.M.-10:00 P.M. - S4-E15
Continuity mistake: Chloe tells Michelle that she's confirmed Marwan's identity using voice tags from McLennan Forrester, but all of the computer records at MF were wiped out a few episodes earlier by the EMP, according to both the MF employees and CTU. The fact that they didn't get any information from the company except for the printouts Jack and Paul extracted was a major plot point a few hours ago, so even if a real EMP wouldn't do this, the fact that it's stated repeatedly in the show means it should hold true within the series; Chloe suddenly having information from them an hour or so later is discontinuous, and thus a mistake.
Chosen answer: Nobody knew, not even the writers, until at least halfway through the season when they were writing the end. They wanted to keep all options open.
Nick N.