Towards the end of the episode when Jack is in Audrey's room, you can see the sun rays shine through the window. In the first episode of the season, the sun didn't rise towards the end of the episode placing the sunrise at approximately 6:30. In this episode, Jack is with Audrey at 5:30.
Jack tells Heller that "the only thing I have ever done is what you and people like you have asked of me!" This line does have nice dramatic effect, but really, how many times has Jack gone against his superiors' orders in the past six seasons?
During the air strike on the oil rig, the Vice President, the Russian President and their staffs were watching the events unfold. They should have seen the helicopter with Jack and Bill arrive on the rig and the ensuing attack. However no one seemed to worry that there were unknown people who could well have taken the circuit board before leaving in the helicopter.
Chloe's line, "That's usually how it works," concerning her pregnancy is reminiscent of Teri Bauer telling Jack that she was pregnant towards the end of Day 1.
The silent clock returns for the first time since "Day 5: 6:00 PM - 7:00 PM." It is also the first time the silent clock has been used to close a season since Season 2.