It happened just after 2 p.m. Wednesday at the Prosperity Bank building. It also happened 50 feet from Jennifer Renfro on the 13th floor.
Two window washers were stranded after their scaffolding likely malfunctioned.
"You could hear the scaffold hit the building," said Renfro.
Renfro says she heard a loud "THUD." It got the attention of everyone in the office and people began to snap some photos through the glass window.
Jonathan Formby is the man with Urban Search and Rescue who rappelled down that wall to save the second window washer. The first worker returned up to the roof and got to safety quickly.
"It's much easier to have to bring someone down than haul someone up," he said.
It was Formby's first rescue ever, but he says he's received plenty of training. He had just received his five-year service pin before going out on the call.
"We were just sort of stunned. There's not much you can say. We were just like 'Oh my God,'" Renfro said.
The rescue of the second worker was a slow methodical descent to the ground where a stretcher, paramedics and ambulance waited.