When Jack Gramm fires the warning shot at his student in the office, we see a close up of the bullet making a hole in the door. However, in the next cut the door is opened and we see both sides of it. There isn't any hole in it.
When Jack reaches the 7th floor of the Stearns Bldg, he racks the slide on his pistol. But he had just fired a warning shot past the student's head a few minutes earlier, there was no need to cock the pistol. And when he does cock it, the slide locks back, indicating the pistol is now out of ammunition.
In the scene where Jack synchronizes his watch with Agent Frank Parks, a closeup of Jack's watch shows a round face (it's clear this is Jack's watch from the color of the jacket sleeve). However, throughout the rest of the movie, Jack is clearly wearing a watch with a rectangular face.
When Jack Gramm gets into the taxi at the beginning of the film, an orange "24 Hours" newsstand is visible in the background. 24 Hours is a newspaper published only in major Canadian cities, including Vancouver, where the film was shot.
Roots stores appear twice: behind Jack and Kim when they go out on the street to get the Porsche, and behind a character walking down the street. Roots is a Canadian chain, with no stores in Seattle. The only US stores are in Beverly Hills CA, Aspen CO, Birmingham MI, and Park City UT.
At least one shot shows a green "Metro" box. Metro is a free newspaper distributed in 7 major Canadian cities, including Vancouver, where the film was shot. In the US, Metro is distributed in New York, Boston, and Philadelphia, not Seattle, where the film is set.
After Gramm leaves the Campus Security Office, he passes by a University of Northwest Washington campus map on the wall. If you look closely, it is actually a University of Washington Seattle campus map. The film was shot on the University of British Columbia campus.
When Jack finds out the Mariners score, he has 76 minutes left, meaning the time is around 10:30 am. The Seattle score is on the bottom, which means they are playing at home. MLB games never start before noon.
When Jack is on the way to the seventh floor to meet his killer, he presses the button for the elevator on the fourth floor. It's too slow, so he goes to the stairwell. He enters the stairwell on the fifth floor.