Jamey Farrell's hair style is notably different in this episode than the previous one. This is obviously due to the fact that this episode was filmed quite a while after the pilot.
The CTU interior seems to have gotten a face lift since the previous episode. This is due to the fact that the pilot was filmed quite a while before the series was picked up by Fox. The audible ticking clock used to bumper each commercial break is also changed.
Jack calls CTU and says, "Nina, it's Jack." The transcript Tony looks at afterwards reads "Nina, it's me Jack."
When Jack calls Nina from outside the parking garage, he tells her, "I'm at 2350 Dunlop Plaza, the North Garage." However, a few seconds later Tony calls up a transcription of their conversation onto his computer screen, and there is a close of the part of the text which (incorrectly) reads, "2350 DUNLOP PLAZA THE NORTH PARKING GARAGE," even though Jack said "I'm at," before this, and he never said "parking" in front of "garage".
The clock on screen reads 01:44 when Keith and Nicole Palmer show up. Then, at the next scene with Teri and Alan, it reads 01:42.
After Jack fixes Walsh's wound in the stairwell they exit through a door in which you see a crew member off to the right of the screen.
(at around 14 mins) When David is talking to Sherry, a camera comes into the shot behind him.
When Jack and Richard are trying to leave the building in Dunlop Plaza, right after Jack reties a tourniquet with Richard's tie, crew members are visible to the right side of a door frame that they walk through. (DVD wide-screen)
In episode 2 when Jack walks through a door he checks to make sure no-one is there so he doesn't fire, however when Walsh walks through the same door seconds later you can clearly see a member of the crew standing there.
Whenn Walsh and Jack are entering the hallway to the storage room (where the firefight happens), you can see someone cowering covering their mouth on the right side of the door frame.