ImmERge Labs cofounder Marion Leary was walking home from the Philadelphia Eagles parade last Thursday, amid a city overcome with joy when, suddenly, she bumped into the very problem her startup is trying to fix.

Surrounded by police officers and a small crowd, a middle-age overdose victim lay motionless on a North Philly sidewalk.

A woman was atop the victim, delivering compressions to the center of their chest. Despite her poor technique, the good samaritan was trying to bring the victim back to life, as first responders waited for the Narcan to kick in.

Had someone stopped for a second to think about it, the word “serendipitous” wouldn’t have sufficed. Here was Leary, the founder of a company using virtual reality to enable CPR training, a director of innovation research at Penn’s Center for Resuscitation Science and a longtime advocate of CPR training, having the chance to help save a life in the field.

But there was no time to think. Leary rushed over, identified herself as a resuscitation nurse and delivered a few chest compressions when the police asked her to pause so they could administer another round of Narcan. A quick pulse check later, it was confirmed: the victim was alive again.

“From my clinical observation, the victim had been in cardiac arrest,” Leary said. “Their skin was completely blue and dusky and they were not breathing.”

(Leary asked that no revealing details about the victim be included in this story, except for their approximate age.)

Recounting the incident, Leary wanted Technical.ly to have one thing very clear: it wasn’t her who saved the victim’s life but the anonymous woman who stepped up to perform CPR and the Philadelphia police officers from the 22nd Precinct who were quick to administer the life-saving Narcan. Since 2015, Philly police officers have been receiving training and vials of the drug to carry around. The drug has been endorsed by the American Society of Addiction Medicine as an effective method to reverse respiratory arrest.

“Despite her technique shortcomings, she might have been essential to returning the victim to life,” Leary said of the anonymous samaritan. “And then there were the officers who remained calm and promptly administered the Narcan.”

SEPTA police chief Thomas Nestel, ever the social media power user, was able to find the names of the officers thanks to Leary’s initial tweet about the incident.

22nd District @PhillyPolice Officer Gedraitis did the rescue breathing while his partner PO Struble administered Narcan and Ms. Leary did chest compressions. You all saved a life in the middle of the biggest event of the year. They were the silent heroes of the day. https://t.co/wmHfD5WmOe

— Thomas J. Nestel III (@TNestel3) February 9, 2018

Nestel also told Technical.ly the victim was successfully revived by the officers, Leary and the unknown woman. Unfortunately, the victim refused further treatment and no more information was made available about their condition. It’s a frequent occurrence: according to a research study from the University of Pittsburgh, which found that most opioid users stay on drugs even after overdosing.

Leary, looking back on it, regrets her initial approach to the good samaritan.

“I wish I had handled it differently,” the founder said. “I wish I would have thanked her and coached her.”

So, what if this happens to you? Leary provided the quick, low-tech run down of how to best handle a cardiac arrest situation.

“First thing you want to do is check the victim for responsiveness,” the cofounder said. “See if there are emergency medical responders nearby and have other bystanders call 911. If they’re not conscious, begin hands-only CPR: pressing fast and deep in the center of the chest at a rhythm of 120 compressions per minute and at a depth greater than 2 inches. If there is an automated external defibrillator (AED), use it.”

There are plenty of free or low cost resources for training in both CPR and Narcan administration. Penn’s Center for Resuscitation Science has a mobile CPR training unit. The American Heart Association and the American Red Cross also offer training. The City of Philadelphia’s Department of Behavioral Health and Intellectual disAbility Services offers monthly Narcan training sessions.

“Everybody should know how to save a life,” Leary said.