The heroic father who shot and killed the gunman that carried out a deadly shooting inside an Oregon elementary school last month revealed his final words to the assailant as he stopped the attack.

Kaylub Giamanco, 36, was driving past Silver Rail Elementary School, which his two daughters, 5 and 10, attend, on his way home for lunch on October 15 when he spotted the 16-year-old gunman, Griffin J John II.

‘It was like fight or flight,’ Giamanco told CBS Mornings on Tuesday. ‘Something clicked and I analyzed the situation. I knew something was up and all the emotions fled out of me.’

Giamanco, a carpenter, said he ‘kind of went into a mission mode’ before confronting the teenage shooter.

John killed three children aged 5, 8 and 11, as well as a 25-year-old teacher, when he perpetrated the heinous attack.

Giamanco said John was still ‘struggling with his weapon’ and ‘trying to regain control’ even after he shot him once.

The shooter also tried to ‘say something,’ Giamanco recalled, but he retorted with an emphatic two-word missive of his own.

‘F*** you,’ Giamanco remembered telling John.

Giamanco added that what the shooter was presumably about to utter ‘didn’t matter.’

‘I just knew that he had just taken lives of innocent little babies, 5, 8 and 11,’ Giamanco told the program.

The courageous dad called 911 before rushing into the school while he was meant to be en route to have lunch with his wife, Kelsey.

He said he ‘crawled’ into the building and peeked into the window of the special needs classroom where John was carrying out the vile shooting.

Giamanco described seeing John ‘struggling’ with a teacher, Cassidy Schutz, which gave him the ‘split second of having two people side-by-side.’

‘I knew that he wasn’t paying attention to me, so it gave me the opportunity to swing the door open and step in and complete my mission, so to speak,’ Giamanco added.

Bend Police Chief Mike Krantz previously said the teacher threw her phone at John and ‘tackled him and fought to take the firearm from him’ before Giamanco arrived and shot the assailant dead.

Schutz, 28, was not injured but her ‘incredible’ actions ‘almost certainly helped prevent more bloodshed,’ Krantz said.

Giamanco said he locked eyes with the ‘terrified’ teacher afterwards, who initially believed in the heat of the moment that he was a second active shooter.

‘She sprang right out of the building,’ Giamanco said, adding that she also ran away after he put his gun on the ground and went to check on her.

‘That’s not the greatest feeling when you’re trying to go in and help but I understood,’ he added.

Giamanco explained that he did not feel the gravity of the situation until he was able to call his wife and mother once police arrived on the scene.

‘I had like, chest palpitations,’ Giamanco said. ‘It was scary.’

Giamanco said he experienced mixed feelings, as his daughters were safe but other families ‘didn’t get to hold their children that night.’

He added that he was still making sure his own children understood what happened.

‘Our 10-year-old is very intellectual, so we do have little conversations,’ Giamanco said. ‘It’s essentially like, “Hey, you know, I just did what I felt was right.”‘

Giamanco stressed that he did not ‘want to go take a life that day’ but he felt it was important for his kids to know that he was there to protect them.

Still, Giamanco said that he sometimes ‘get[s] trapped’ in his brain at night time when he recalls the details of the horrific shooting.

‘The problem for me is just closing my eyes and hearing children’s screams and what it sounds like for them to plead for their life,’ Giamanco told the outlet.

Giamanco said he had not returned to work as a carpenter yet as he evaluated a career change following his intervention in the shooting.

‘I feel a need to maybe start a nonprofit for mental health and for school security for children,’ he said.

Rhoam Summer, who had started kindergarten just last month, was the youngest of the three children killed in the elementary school shooting.

The boy’s teacher was named as Megan Lambert, 25, of Bend. Her family said teaching at the school was Lambert’s dream job.

Two boys, ages eight and 11, were also shot and killed by John but were not identified by police at the request of their families.

Educational assistant Rebecca Drury, 54, and Saylor Graham-Poarch, 7, were rushed to the hospital with injuries.

Saylor, who uses a wheelchair, was shot in the face during John’s deadly rampage.

John used a pump-action ‘long gun,’ similar to a rifle or shotgun, that police said had been purchased by his mother.