INDIANAPOLIS (WRTV) -- Kelsey Davis and her mother were getting lunch in Carmel, near the Monon Trail, when they heard a man crash on a motorized scooter.

"Initially I thought it was a teenager that fell," Davis said. "And when I saw it was an older gentleman, like in his 40's maybe, I thought well, maybe he had a heart attack or had a rhythm issue and that's what caused him to fall off and crash. Or maybe it made his heart go out of rhythm."

The man was unconscious, and they couldn't feel a heartbeat. Davis called 911 and then used her training.

"His condition wasn't improving, he was unresponsive," Davis said. "I knew the ambulance was coming, so I thought I was going to start compressions."

Those compressions - giving him CPR for about 2 minutes - saved his life.

The Indianapolis EMS Medical Director, Dr. Dan O'Donnell, says choosing between giving someone CPR or not is a matter of life or death.

Dr. O'Donnell says people are often afraid to give someone CPR because they don't want to hurt the person or do it wrong.

"It's better to air on the side of caution especially if you truly don't feel a pulse," Dr. O'Donnell said. "They are unresponsive, and you don't think they're breathing normally, we need to get early CPR on them."

Studies show that only five to ten percent of people will survive cardiac arrest. That percentage drops to zero without CPR.

"You don't have to be medical to know CPR. That's what I told my mom," Davis said. "There's no excuse not to know it. Just do it."

Doctors say bottom line: if you see someone unconscious, they're not breathing, have the confidence to know you can save a life.

To give someone CPR, lay them flat on their back and use both your hands to push down an inch or two for compressions and count 100 beats per minute.