The suspect is seen on video with a red backpack.
The shooting happened Monday afternoon outside the entrance on 31st Street and 7th Avenue.
Police say the suspect got into an argument over food with a man inside Penn Station and fired a shot at him once they got outside. He missed, however, hitting another man in the leg.
A taxi dispatcher says he saw the victim fall to the ground.
"So I went over and asked him 'Are you alright sir?' He said no, something's wrong. So I went and got the cop," said witness George Harris. "He was in the wrong place at the wrong time."
"Innocent bystander gotta walk by and get themselves caught up. It's not right," said Mango Emondzson.
It happened around 5:30 p.m. in the middle of rush hour.
"You know, people are just getting shot for no apparent reason," Staten Island resident Jocelyn Smith said.
CBS2's Nick Caloway spoke to commuters who say stories like this are shocking but no longer surprising.
"Some people said, 'Welcome to New York.' Well, this is not the welcome we want," New Jersey resident Adrian Wilson said.
"It's difficult to wake up every morning and not be nervous to get to work," New Jersey resident Erica Derector said.
A day after the shooting, police could be seen posted outside Penn Station, but inside, commuters say the police presence is thin.
"How safe do you feel when there's literally, there's just two cops," Wilson said.
Those safety concerns are now top of mind as many workers are set to return to the office this fall.
In anticipation of a surge of commuters, New Jersey Transit Police will use high visibility uniforms to help people quickly identify officers.
More officers will be riding buses and trains than ever before.
The agency has also added 500 cameras to help detect and deter criminal activity.
The MTA has added some 2,000 security cameras since this spring in anticipation of a surge in ridership this fall.
"Every time we're out in the city, everybody should be careful and always watching out for one another and taking care of each other. Again, we ask the city to step up further in locations like that, particularly above ground, and help us deal with the challenges," MTA Chief Safety and Security Officer Patrick Warren said.
CBS2 has been told Amtrak Police have increased perimeter patrols at Penn Station in the wake of Monday's shooting.
The victim is expected to recover.
Meanwhile, anyone with any information is asked to call the NYPD's Crime Stoppers hotline at 1-800-577-TIPS (8477), or for Spanish, 1-888-57-PISTA (74782). You can also submit a tip via their website or via DM on Twitter, @NYPDTips. All calls are kept confidential.
Editor's note: This story first appeared on August 24.
for more features.