The 31-year-old man went out of a ninth-floor window and landed on a BMW below around 10:30 a.m. at Sip Avenue and Enos Place (26 Journal Square), City Spokeswoman Kimberly Wallace-Scalcione said.
His injuries were considered life-threatening.
Christina Smith said she caught the fall from the corner of her eye. She called police right away, and then began filming.
The man fell on the car and then got up, and fell on the ground.
"The sound was very loud," she said. "He was screaming 'help.'
"I was trying to tell him to calm down and stop moving."
His condition was not immediately clear.
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