A man and a squeegee. Fighting for Life 50 Floors Up, With One Tool and Ingenuity http://t.co/vFA4pyxrvN http://t.co/kdoNsHtsS3

— Jim Dwyer (@jimdwyernyt) September 11, 2013

The car rose, but before it reached its first landing, ”We felt a muted thud,” Mr. Iyer said. ”The building shook. The elevator swung from side to side, like a pendulum.”

Then it plunged. In the car, someone punched an emergency stop button. At that moment — 8:48 a.m. — 1 World Trade Center had entered the final 100 minutes of its existence. No one knew the clock was running, least of all the men trapped inside Car 69-A; they were as cut off 500 feet in the sky as if they had been trapped 500 feet underwater.

They did not know their lives would depend on a simple tool.