an explosion. [noise] the first thing that tells you something is wrong is a huge bang? >> yes. >> coming from where? >> it was the main entrance, so it was off to my right. and behind me. i remember turning around and looking at it and just seeing people screaming and running. >> in those first seconds, katherine wasn't sure what's happening. she thought it sounded like a broken glass, something falling. but she immediately grasped that she and her girls were in danger. the chaos confused another mother not far from katherine on the main floor. faith was in the mall with her two children. nine year old daughter sy and 21 month old son. the agriculture researcher was sought shopping for an anniversary present with her husband. she was in the flower shop when she first heard the noise. >> it was so loud that i actually thought there must