As they and police tried to get to him, he climbed higher and higher to a crane at the top.
PhD student Michelle Helms was on the 10th floor of Jefferson Hospital watching across the street as the man climbed out to the edge of the girders.
"You could see him pacing around on the girders and it was really interesting to see the dynamics between the cops and him. They were [saying] 'please, come down' and he's just pacing, contemplating something. You could just see all of the body movements," Helms said.
As onlookers held their breath below, the distraught man told police officers he had a heroin problem, had lost his family and had nothing to live for.
Central Detectives officials spent an hour convincing the man he could get help.
Finally, he crawled back from the edge overlooking 9th Street and was subdued by the SWAT team that was called in.
"They couldn't cuff him because they had to walk him down ladders because it was a construction site so you could just see them escorting him down below," Helms said.
The man, wearing a Dallas Cowboys t-shirt, was escorted by SWAT officers to a waiting van with his head down and hands behind his back.
Police will not release his name because he's being evaluated for psychological issues at Pennsylvania Hospital.
For grad student Michelle Helms, who just wanted to catch up on some work before the week began, it was a night she won't soon forget.
"It's a little scary. The last thing I'd want to see was him jump off. The police seem like they did a really good job and I'm glad everyone got to walk away and no one was hurt," Helms said.