regina wilson was studying for the lieutenant's exam. fdny's award for the most physically fit firefighters. >> a lot of bravery was displayed that day. and followed by a lot of sadness. >> reporter: commissioner, it seems to be a sad day for you 20 years later. >> i think for everybody that was there that day, it just stayed with them, the sadness. we have plenty of good days, plenty to be thankful for, those of us who survived. but it's a day that will never leave you. >> reporter: sadness becomes part of your life? >> absolutely. >> reporter: your father survived the collapse of the first tower. and instead of moving to safety, he went to answer the mayday calls from his trapped firefighters. >> receive report firefighter trapped and down. >> reporter: he knew that the other building was in imminent danger of he had decided in that moment that he was not going home. >> yeah. he chose his guys. we could get angry about it. and i know my sister and my mother, sometimes we hit our head against the wall. but when the smoke clears and you