My building went into lock-down for a possible shooter. Campus security and city police were called. About 15 of us were in an office for 45 minutes, the rest of the staff was called and emailed to find shelter. Everyone's ok, apparently the guy left the building and the officers did a thorough search. We got an "all clear" and went back to work (but how do you go back to work after that...?).
I took the opportunity to do some research. I'm currently playing a cop on stage, so I studied the police officers' belts, listened to how they talked into the radios, and observed their demeanors when questioning the witness. I figured I'd do some character research while waiting to be told if my life was in danger or not.