Continuity mistake: There is a lot of moving from one place to another during the last 10 minutes (supposed to be actual 10 minutes of the timeline), which seems pretty much impossible - from Jack's apartment to the girl's apartment, then to the office on campus, then to another building, up to floor 7, and they still have time to talk for a couple of minutes. Note that the glass doors to the elevators are locked, so he has to take the stairs, which are also behind a glass door that happens to be open. And how did he get through the police block on campus? There was a bomb threat just about an hour and half before - there is no way he would be allowed in there. Notice that the campus streets are empty so he can run without problems from his office to the other building.
Continuity mistake: After Jack receives his first phone call whilst giving his lecture, he places his mobile phone screen down, then when it rings again it is facing up with the screen visible.
Continuity mistake: In the stairwell, Ms. Douglas wipes blood from her nose, but in the next shot, there is no visible trace of blood on her face. In the next scene at campus security, the blood is again on her face as it originally was. (00:39:20 - 00:40:15)
Continuity mistake: Jack unties the gag by hand, then is putting away his switchblade as if he had cut the gag. (01:38:30)