The man who rescued a boy walking on the monorail at the Hersheypark theme park in Pennsylvania is speaking out following the adrenaline-filled incident, which was caught on camera and has since gone viral.

John Sampson, who was at the park that day with his family, said he remembers the moment he realized something was wrong.

"Everybody's like, 'Oh my God, there's -- there's a kid up there, there's a kid up there!'" Sampson recalled.

The monorail was not in operation at the time, and the section with access to the monorail was in a secure area that had been chained and barricaded, according to Hersheypark officials. Despite those measures, they said the boy managed to gain access and entered the barricaded section Saturday evening.

In video footage of the incident, bystanders notice the boy from underneath the monorail and yell up to him as he begins to walk along the monorail track.

Sampson, a veterinarian and a father of three, said he had been watching over his family's belongings when he noticed the child on the monorail.

"A kid is walking on the monorail, and obviously, panic kind of sets in a little bit," Sampson said. “When you have that, like, kind of dad instinct, it doesn't matter if it's your kid or not, it's a child that you want to make sure they're safe as possible."

Sampson said he jumped into action and began running to the roof of a concession stand, hoping it could help get him closer to the monorail.

"There was a fence that I jumped on and then I was able to jump on the roof from there and then it was a straight shot up," Sampson said.

Although Sampson said he has a fear of heights, he said he didn’t consider it when the rescue unfolded.

"It didn't bother me up there, because I was just concentrating on one thing, and I didn't hesitate on any of it," he recalled.

Sampson said that within seconds, he managed to get onto the monorail and reach the boy, who was frightened and climbed into his arms.

"So, when I finally got him in my arms, honestly, there was no words," he said. "I was just mumbling, 'I'm so happy,' you know, 'I got you. You're OK, you're OK.'"

"And then it was the, 'OK, now, how do I get down from here?' Luckily, another gentleman was waiting there for me, and he helped me out," he added.

Hersheypark staff were able to take the boy from Sampson, and as Sampson descended from the concession stand roof, he said his wife located him and he realized what he had done.

"I heard this 'John?!' and that's when it kind of like, I was able to think again and, like, hear everything," Sampson recalled. "And I looked down. I'm like, oh my goodness, OK, yeah ... I just waved to her, like, nonchalantly."

In a statement, Hersheypark said the boy was unharmed after the monorail incident.

"Our team members immediately responded after he was spotted on the tracks, and at approximately 5:28 p.m. the child was safely reunited with his family. He was unharmed," Hersheypark said in part. "We are grateful for the vigilance of our guests and the swift response of our team, and we remain committed to maintaining the highest levels of guest safety throughout Hersheypark."

Following the incident, Sampson said he received a phone call from the boy and his parents.

"They contacted me, and then we had a nice conversation," Sampson said. "Obviously, super, super happy to hear that he's back with his parents. And then I got a nice thank you as well from the son. So that was nice."

Sampson said he wasn't the only hero that day and said his message to others is that we all need each other's help, and we should all look out for each other.