The Hawaii emergency management worker who was fired after issuing a false alarm last month notifying the people of Hawaii that the ballistic missile was headed for the island said he was “100 percent sure that it was the right decision, that it was real.”

“I did what I was trained to do,” the worker said NBC News in an interview on Friday. He has requested to remain anonymous due to death threats.

On Jan. 13, Hawaiians received an alert on their phone and televisions warning of an inbound ballistic missile. It took 38 minutes for a retraction to be sent, though some local government officials did get the word out sooner. Hawaii Gov. David Ige initially said the false alarm was sent because someone “pushed the wrong button” and that the mistake occurred during an employee shift change.

According to a preliminary federal investigation that was released in January, the words “exercise, exercise, exercise” were stated at the beginning and end of the drill message. However, the phrase “this is not a drill” that is used for real missile alerts was also included.

The worker said he didn’t hear “exercise,” but that once he figured out that it was a drill, he “just wanted to crawl under a rock.”

“It was incredibly difficult for me, very emotional,” the worker responsible told NBC News.

Those who led the investigation claimed that other employees heard that the drill message said it was an exercise and according to Brig. Gen. Bruce Oliveira, the employee had a “history of confusing drill and real world events.” Oliveira headed the probe.

The employee refuted Oliveira’s claims to NBC News.

A Federal Communications Commission preliminary report stated the drill was “run without sufficient supervision” and that “there were no procedures in place to prevent a single person from mistakenly sending a missile alert from the State of Hawaii.”

“There was no requirement in place for a warning officer to double check with a colleague or get sign off from a supervisor before sending such an alert,” the report said.

Hawaii officials have since installed more protections to prevent just one person from sending an alert.

The employee expressed sorrow and said he wished the incident hadn’t happened.

“I regret this ever happened," he said. "I feel terrible about it. I did what I thought was right at the time.”