The means of operation for a terrorist

http://www.youtube.com/watch?v=n986L71RzgM You are working as a private security guard at a major banking center in a metropolitan city. Recent Homeland Security alerts as well as news updates on local news channels indicate an elevated possibility of a terrorist attack in the area near the banking center where you work. How would you be able to recognize a terrorist approaching the banking center? What action would your take? What is the means of operation for a terrorist? ( 500 words, 1 reference)