Watch and listen closely to Howard Lutnick in this interview with Connie Chung days after the event. I can say a lot here, but here is one interesting place to start:

At around the 7:30 mark, he shares how the company the year before made 50 trillion dollars in business, but right after that, correct me if I am wrong, but does he say:

"today, the remaining employees of Cantor Fitzgerald...have worked every second since that bomb." Did he say "bomb"?

I turned on closed caption and it came up as the word, "bomb."

https://www.youtube.com/watch?v=-z5aW0ovieY