Day 4: 3:00 P.M.-4:00 P.M. - S4-E9
Continuity mistake: In the previous episode, when Jack and Tony try to stop the helicopter, they drive off the road and hit the front bumper and lose their front license plate. This is also visible in this episode as Jack and Tony wait for backup and when they drive off there is still no license plate, but about 8 minutes later, when they arrive, the license plate is back on. Since the show is in real time and they arrived in the exact time they said they would, they couldn't have stopped to get it fixed or anything.
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.