After firefighters arrive at the North Tower, janitor William Rodriguez leads some of them up its stairs. Being one of only five people possessing a master key, he opens emergency exit doors as he goes up, allowing people to escape from the building. But between the tower’s 20th and 30th floors he hears a series of explosions. The source of these is unknown. Then, when he reaches the 33rd floor he hears what sounds like heavy equipment being dragged across the floor of the level above. He finds this puzzling, he later says, because the 34th floor is supposed to be empty and has been off limits for weeks due to a construction project. After he reaches the 39th floor, Rodriguez is ordered to turn back by the firefighters with him. He then hears the sound of the second plane hitting the WTC, at 9:03 a.m. Rodriguez also claims he heard an explosion from the North Tower’s basement just seconds before it was hit at 8:46 a.m. (see (8:46 a.m.) September 11, 2001). He will later be credited with saving many lives on 9/11, and be treated as a hero. [Christian Science Monitor, 3/25/2004; Western Morning News, 12/2/2006; Herald (Glasgow), 2/16/2007; Argus (Brighton), 2/26/2007]