doesn t describe super men rushing into the burning tower, but in fact, ordinary, mortal men. i look at my hero firefighters and i think they would say the same thing, that they did ordinary things but in an extraordinary time in history. reporter: including his brother. kevin pfeifer he s my brother, with his engine company. we lost the entire engine company that day. reporter: as we walk along here, you see all these names. these are the people we lost that day how much do you think about the people that you and your firefighters saved that day that day, we saved 20,000 people. and i think that s what we have to remember that s nightly news for this tuesday. thank you for watching, everyone i m lester holt. please take care of yourself and each other. good night
were trapped reporter: he made critical decisions, ordering the south tower evacuated before it was hit, likely saving countless lines. among the firefighters who raced into the north tower was his younger brother and fellow firefighter, kevin. my brother as he came in, we were able to look at each other and wondered if we were both going to be okay reporter: and later, as the conditions grew worse, chief pfeifer issued this ominous order and i got on the radio and said, command to all units in tower 1, evacuate the building reporter: you were asking firefighters to leave the burning building, full knowledge that there were people you couldn t reach perhaps the first time in history that a fire chief ordered the evacuation of our firefighters with a thousand people in the building reporter: in his book ordinary heroes, pfeifer