Plot hole: Near the end Max calls Annie, using the number on the card she gave him, to warning her about Vincent's arrival. But why is there on the card the number of the law library on the 16th floor and not Annie's office number or her cell phone number?
Suggested correction: The number on her business card is her office line. A lot of office phones are set up so they ring in multiple places throughout the office. A light will blink on the phone letting you know which line is ringing. The line is connected to her office phone, which we see Vincent looking at in her office when she was on the phone with Max, which then gives away her location. This is a very popular way of having phones set up in offices, as it eases communication between co-workers. If one of her co-workers wants to talk to her while she's in the library, they can simply dial her line instead of going up two floors. Furthermore, it is also possible that her cell phone number could be on the card. But Max tried the office number first. He would likely have tried the cell number next, had she not answered.