NEW YORK (CBSNewYork) – An off-duty NYPD officer was arrested and suspended by the NYPD Wednesday, after an altercation with a conductor caused chaos on the subway on the Lower East Side.

As CBS2’s Christine Sloan reported, the incident left people trapped in a subway car with no idea what was going on. Some people were breaking windows to get out.

The incident took place at around 9:15 a.m. on the Brooklyn-bound J train as it was leaving the Delancey Street-Essex Street station.

Something just happened on the J train. Someone yelled run and all hell broke loose. pic.twitter.com/qvFzb1z986 — wbernard (@wbernard) September 14, 2016

The conductor — identified as Kiyya Rivera — opened a train door, which struck off-duty police officer Tremel Davis, prompting an argument, according to police.

Davis, 33, then pushed her back into the conductor’s cab, knocking her to the ground and injuring her head and arm, police said.

When ppl block train doors and we are all evacuated = 30min train delays #mta #subway #likechina pic.twitter.com/YLgDbBrq8c — Natasha Fong (@Natasha_fong) September 14, 2016

The conductor pulled the emergency brake, halting the train with one car still in the station, according to the Metropolitan Transit Authority.

Davis was taken into custody at the scene. The conductor was taken to an area hospital complaining of pain to her head and arm. Her injuries are not considered to be serious.

Davis has been charged with assault. Since he was already on modified duty stemming from a prior off-duty misdemeanor arrest, he was suspended by the NYPD and is no longer reporting for duty.

He was also stripped of his badge and gun.

CBS2 has learned the officer was already on modified duty when the incident occurred.

when the j train dies pic.twitter.com/5W0yY42laJ — Corey S~W (@csmithwest) September 14, 2016

The melee prompted a panic among passengers, some of whom ripped out subway windows in an attempt to escape.

“Nobody knew what was going on, even until the end,” passenger Rosario DiSalvo told Sloan. Somebody was screaming “that they were killing her,” DiSalvo said.

DiSalvo was on the train but had no idea the conductor was being attacked, Sloan reported. Some passengers heard the word “fire,” and others thought there was a bomb on the train.

So passengers took matters into their own hands.

“Me and two other guys broke the window and we started pulling people through the window onto the tracks,” DiSalvo said. “Everybody fell off the tracks. We ran off the tracks. Ran through the tunnel, people got stuck.”

The scene was captured on video in another car.

People on the platform tried to reassure those still on board that help was on the scene, CBS2’s Valerie Castro reported.

“The cops are down on the other train car wherever the problem is,” one witness said.

The MTA said it has received no substantiated reports that customers on the train entered the tracks. The agency said the train operator walked through the entire train within six minutes of the incident.

The train then backed up and police were on the scene, DiSalvo told Sloan.

“Some kid was arrested and they were looking for another guy on the tracks,” he said.

The train operator made announcements and walked through the entire train informing customers car by car, according to the MTA.

The incident caused delays on almost all the subway lines, Sloan reported.

The MTA says if you find yourself in this kind of situation, you should:

Stay calm and not leave the train on your own because in most cases the tracks are still electrified and other trains may still be in motion around you.

If you’re unable to stay in the car you’re currently in, the MTA urges you to walk calmly to another car that is not impacted by the emergency.

Don’t try to leave the train without instructions or help from the crew or other MTA employees.

If an evacuation is necessary, crew members, other MTA employees and emergency responders will help with the evacuation.

One man told Sloan he was stuck on an M train for 90 minutes.