Down on the main floor, Palmer picked up the black trash bag and slipped out the back door into the alley. He followed a meandering course away from the building and dumped the trash bag in a pile of refuse awaiting the 5:00 a.m. garbage collection. He heard a low dull rumble as he neared the subway station, and then saw a bright flash as flames leaped skyward from the top floor of the Heartland building.