I was on my way home at lunchtime on my half-day, but stopped off to do a house-call on the way. My patient grabbed me by the arm, and hauled me into her sitting room - "Just watch this" she said. Like many other people, the first images suggested an apocalyptic movie, rather than a news item. The first tower had already been hit. We sat there transfixed and saw the second tower hit as well. It was a while before I remembered what I was there for and checked her over. Eventually got home, 15 minutes away, and carried on watching there.
Recently I watched a TV programme called 102 minutes, which showed a lot of video footage from the actual day: just horrific.
I learned Tom Paxton's song, "The Bravest", and sang it on the 5th anniversary: tears in the audience for those lost.