(CNN) David Hogg found himself living a nightmare on Wednesday, hiding in a closet with classmates as a crazed gunman roamed the campus of Marjory Stoneman Douglas High School in Parkland, Florida, unleashing a torrent of bullets on students and teachers .

Huddled in the dark, trying to keep quiet to avoid the gunman, students called their parents to tell them in hushed voices that they loved them.

"That's kind of around the same time that I just had to pull out my phone," Hogg, a 17-year-old student journalist, told CNN in a phone interview Friday.

"It was sheer terror," Hogg said of that moment, but he quickly recognized it as one that needed documenting -- if not for him to report, then for survivors and lawmakers to understand how desperately the country needs to implement reforms to prevent yet another mass shooting.

He started interviewing those closest to him in the cramped space, who told him how terrified they felt.

"I want to show these people exactly what's going on when these children are facing bullets flying through classrooms and students are dying trying to get an education," he told CNN's Alisyn Camerota on Thursday. "That's not OK, and that's not acceptable and we need to fix that."

JUST WATCHED Student to lawmakers: We're children, you are the adults Replay More Videos ... MUST WATCH Student to lawmakers: We're children, you are the adults 00:45

'How do you tell a story like this?'

When Hogg took out his phone Wednesday afternoon and started filming, he only had one thought in mind: "Tell the story."

None of the people in the room knew whether they were going to live. But in case they didn't, Hogg wanted the public and lawmakers across the country to know what it was like to be a high school student, hiding from a school shooter in a dark classroom closet.

"If I was going to die, I wanted to die doing what I love, and that's storytelling," he told CNN. "And this is a story that needed to be heard. ... At least our echoes, our voices would carry on and possibly make some action."

Photos: Text messages show horror inside school Kaitlin Carbocci was at work when she received these chilling messages from her sister Hannah, 17, who was on lockdown inside Marjory Stoneman Douglas High School in Parkland, Florida, as a gunman walked the halls. Hide Caption 1 of 7 Photos: Text messages show horror inside school Hide Caption 2 of 7 Photos: Text messages show horror inside school Hide Caption 3 of 7 Photos: Text messages show horror inside school Hide Caption 4 of 7 Photos: Text messages show horror inside school Hide Caption 5 of 7 Photos: Text messages show horror inside school Hide Caption 6 of 7 Photos: Text messages show horror inside school Hide Caption 7 of 7

Before the shooting was over, the gunman, 19-year-old Nikolas Cruz, had claimed the lives of three staff members and 14 students -- among them, some of Hogg's little sister's best friends. Cruz faces 17 counts of premeditated murder.

When the school finally reopens and students return to fill the halls, Hogg and his peers will be responsible for covering what will probably be the biggest story ever to happen at Marjory Stoneman Douglas.

"Honestly, at this point, I don't know if I have the journalistic quality to give it as much as it needs," he said. "How do you tell a story like this?"

But today, Hogg isn't thinking about that. He and many other students-turned-survivors are focused on making sure that the shooting at their school -- the ninth-deadliest mass shooting in modern US history -- doesn't become history without being a catalyst for change.

"It's a midterm year and it's time to take action," Hogg said. "I don't care if you're a Democrat. I don't care if you're a Republican. Stand up for what you believe in. Let's make some compromises and save some children's lives."

Journalism is his 'passion'

Hogg, whose family is originally from California, loves broadcast journalism. Notably polished and media-savvy, he's appeared on several news networks and in numerous articles since Wednesday, calling for "action" from politicians in Washington and in state capitols across the country.

He's been watching "60 Minutes" on CBS "basically since second grade," he told CNN, and has always been fascinated by current events.

When Hogg's family moved to Florida several years ago, they chose Marjory Stoneman Douglas High School in part for the different activities and programs it offered, one of which is TV production.

"When I started there freshman year, halfway through, I knew that I really liked it," Hogg said. "I liked the environment."

During the first year in the program, students take notes about production techniques and the different assignments and roles in a television studio, Hogg said. When they become sophomores, the students get the opportunity to produce TV broadcasts.

"I made some god-awful packages, I'll tell you what," he said. But as he advanced and learned more, the class became more than a grade to him. "It's my passion."

In the past year, Hogg's interest in journalism has grown stronger. His AP US History class recently learned about the Pentagon Papers and the role journalists -- "the fourth check on the government," he said -- play in the United States.

"They essentially inform people of what's going on, and arguably that's one of the most important things for any functioning democracy," he said.

Over the past several days, Hogg has gotten a close look at the lives of professional journalists and spoken with many of them as they set up for live shots outside the high school, but he wishes he'd made those connections under different circumstances.

"I wish I could meet them and get known not from a story about an active shooter that shouldn't have even happened," he said. "I wish I could have met them through just my hard work as a journalist."