the doors but control systems would not let them; in any case, thick smoke and intense heat would have prevented rescue helicopters from landing. The comparably high number of jumpers from the North Tower can be partially attributed to Flight 11's impact zone being located in the center of the tower. This resulted in the entrapment and eventual deaths of everyone who was at, above, and even a floor below the point of impact. All three stairwells were destroyed or blocked by rubble and the elevators were rendered inoperable, preventing any form of escape. Those above the point of impact in the South Tower may not have been trapped, with the northwesternmost stairway (Stairway A) still being traversable as a result of Flight 175's impact being off-center into the southeast corner of the building and tilted at a severe angle. While only 18 people from the crash zone are confirmed to have escaped the building using Stairwell A, the 9/11 Commission Report also noted one NYPD unit that encountered around a large group of civilians making their way down through an unidentified stairwell shortly before the tower's collapse, opening up the possibility that others from at or above the impact zone could have found the staircase but simply failed to descend it in time before the tower fell. The North Tower had also been hit considerably higher up than the South Tower, with the smoke and fire being confined to 17 floors instead of 33. This meant the smoke was far denser and conditions were less survivable in turn. While approximately 800 people in the North Tower who survived the impact were restricted to a much smaller number of floors, the estimated 300 people who were not killed by Flight 175's crash had more room to maneuver between floors in the South Tower and move away from the smoke and flames. It is also worth noting that many people in the South Tower evacuated as soon as the first jet struck the North Tower, leading to there being far fewer people above the point of impact—roughly 600, less than half that of the North Tower, where at least 1,344 people were either killed outright or trapped with no way down. It is further believed that around half of these 600 occupants were killed instantly the moment the plane hit, which would have left less survivors to jump. Conspiracy theories Contrary