Fighting as in fighting for your life (ie: doing something to at least try to survive), not as in looking for someone to punch.
The people who were on the floors above the impacts were doomed. There was no escape for them. It was jump or be burned alive. Trust me, it was a gruesome and very scary scene -- even on the ground, four very short blocks away, where I was showered with tiny shards of slivers of glass. As numb as I was that morning, the jumpers still really got to me.