jaydeehess
Penultimate Amazing
From NISTNCSTAR1-8, "Firefighters on the ground saw them and went up the stairs. In addition, a security officer for one of the businesses in the building was also was trapped on the 7th floor by the smoke in the stairway. As the firefighters went up, they vented the stairway and cleared some of the smoke. They first met the security officer on the 7th floor and firefighters escorted him down the stairs. Other firefighters from the group continued up the stairs, shined their flashlight through the staircase smoke and called out. The two trapped men on the 8th floor saw the flashlight beam and heard the firefighters calling and went down the stairway. The firefighters took the men outside and directed them away from the building."
Well that explains how, later, the FDNY managed to send FFs through the building and assess the structure.
Its apparent that the east stairwell was impassable to Jennings and Hess due to smoke and dust.

