"I was just sitting there waiting to go meet some friends. I was sitting there, I heard a boom and then my face started bleeding," said Shirley Williams.
21-year-old Williams of Wilmington, told her story which was captured on surveillance video.
It was around 3:15 Friday afternoon and she was sitting on a bench, waiting for an eastbound train on the Market Frankford El at 40th and Market Street.
Nearby, a man who turned out to be a security guard with a permit to carry, is seen fumbling through his duffle bag.
Seconds later, the man recoils as the gun in the bag goes off.
At the same time, Williams reaches for her face.
"I don't know if it was a BB gun or what but it hit me pretty hard in my face and my arm. I didn't know what happened right away," she said.
Williams did not realize she had been struck by bullet fragments in the face and the arm.
Police say the security guard also apparently didn't realize that someone had been struck and he went on his way.
Later, authorities say, he saw himself on the news and turned himself in.
"She's very fortunate that the energy from the bullet was taken out from the metal bench, then it bounces into the ceramic tile then bounces off there and into her. It took two strikes before it actually hits her," said Lt. Johnny Walker, Philadelphia Police Department.
Williams, who had just seen a movie and was on her way to visit family, was only slightly bruised on her face and arm.
She works as a clerk at a Wawa and said she jokingly thinks her Wawa sweatshirt may be bullet proof.
"I'm just happy that I'm okay. I'm just happy I have my life and I can walk away right now," said Williams.
No word on any possible charges.