Just read one guy was on 22nd floor and surfed down 15 floors on a piece of concrete and landed on a ledge around 7th floor. There was 15 or 16 others on lower floors in a stairwell when the building collapsed they could see the sky.https://www.telegraph.co.uk/news/worldnews/september-11-attacks/9530013/911-survivor-tells-how-he-surfed-15-floors-down-the-collapsing-tower.html