Even as time passes, the memories and horrors are easy to remember. 1,462 people died but there were also thousands who made it out alive. In England, this professor watched it unfold on television. He specializes in the study of disasters but he had never seen anything like this. He still chokes up at the memory. He was that day a human being instead of an academic watching the tragedy unfold. He knew there were going to be a lot of firefighters killed in the response. Within days, the professor and his team traveled to New York to unravel what happened inside the towers that day. Their study provides a unique and unprecedented look at what happened. We had access to a 6,000-page transcript of the testimonies, full of powerful, first-hand accounts. One of the studies most surprising is that the rush to the exits was not a rush at all. The professor says more than 90% of those who survived delayed leaving. What were they doing? A cafeteria supervisor recounts what she did to get people to leave: mainly of her having to convince people to evacuate. When they did leave, they found stairwells jammed with others trying to escape, despite the fact that the towers were far from full. The professor estimates if everyone had been at work when the towers were hit, almost 7,600 people would've died, many because they wouldn't have been able to get out. The professor is dismayed that U.S. building codes still lag behind British. He'd like to see stairwells with better materials, or elevators that can function in the face of fire. The study reinforces the need and he says that's thanks to people who were willing to share their painful stories. The professor says the opportunity was cathartic for many people.