A student at Marjory Stoneman Douglas High School has revealed that his life was spared by shooter Nikolas Cruz just moments before he opened fire in a massacre that left 17 dead.

Chris McKenna, 15, told the Sun-Sentinel that he was on his way to the bathroom on Wednesday when he stumbled upon Cruz loading up one of his assault rifles.

'You’d better get out of here. Things are gonna start getting messy,' McKenna said Cruz told him, despite the fact that the two young men did not know one another.

McKenna then rushed out of the building where he ran into assistant football coach Aaron Feis, who after getting the youngster to safety returned back to the school in what would become his final, fatal trip.

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Saved from the slaughter: Chris McKenna (above) was heading to the bathroom just before the shooting on Wednesday and came across Nikolas Cruz

Head out: 'You’d better get out of here. Things are gonna start getting messy,' McKenna said Cruz, 18, told him (Cruz above)

So many close calls with death, none more chilling than this one. Freshman Chris McKenna encountered the shooter just before the rampage began at Douglas High. @nbc6 #DouglasStrong pic.twitter.com/c3rkbd5XDs — Ari Odzer (@ariodzernbc6) February 15, 2018

'I told him I saw a gun,' said McKenna of his first words to Coach Feis.

'He said, "Let me go check it out." Then he drove me to the baseball field, dropped me off, and went back to the school. That’s the last I saw of him.'

It would be the last time that he would see Coach Feis, who was shot dead just minutes later while protecting other students from gunfire.

Feis, 37, was married with a baby daughter.

One of the young students he saved, Kelsey Friend, said he was her 'hero.'

Heroic: Coach Aaron Feis shielded students at Marjory Stoneman Douglas school as shooter Nikolas Cruz opened fire - eventually killing 17

McKenna said in an interview with Ario Odzer on NBC 6 that he was still trying to process the fact that if he had not gone to the bathroom at that very moment he would likely be dead.

He is also dealing with the fact that three of his friends were killed in the shooting and a fourth is in the hospital.

The fallen were remembered on Thursday night with a vigil.

On Wednesday, Cruz walked into his former school almost one year after he was expelled and opened fire with an AR-15, killing 17 people before he hid among those fleeing the scene and got himself away from the area.

He was captured an hour later after police reviewed surveillance video that was taken at the school.

It was revealed on Wednesday evening that the FBI had been alerted to an alarming comment made by Cruz back in September but never investigated the young man.

That is because the agency was unable to determine the identity of the person who posted that comment on YouTube under the username 'Nikolas Cruz.'

Students who knew Cruz have also been speaking out, including one young man who wrote: 'Nick attacked one of my friends once. He brought shotgun shells to school and made many threats against others. He had an insta full of pictures of dead animals that he killed.'

The teen, who wrote that his parents had prohibited him from giving interviews, added: 'Mental illness needs to be recognized or things like this happen. People i know are f***ing dead.'

Cruz has not be attending Marjory Stoneman Douglas High School at the time of the massacre, having been expelled for disciplinary reasons during the 2016-17 school year.

It was at least the third time that Cruz had been forced to leave a learning institution, and came at a particularly difficult time in his life.

Cruz, who has a younger brother Zachary, lost his mother Lynda back in November as a result of complications from the flu.

The 68-year-old mother-of-two developed a case of pneumonia shortly after checking herself in to receive treatment for the seasonal sickness.

On Instagram, Cruz could be seen holding firearms, ammunition and the semiautomatic AR-15 rifle he likely used in bthe attack.

That weapon was legally obtained and the family's lawyer Jim Lewis.

One photo shows several guns, including rifles with scopes, laying on a bed. Another appears to show a frog that had been killed.

His father Roger died of a heart attack back in 2005, just a few years after he and wife Lynda adopted Nikolas and his brother Zachary.

An official GoFundMe account has been set up to raise money to 'provide relief and financial support to the victims and families of the horrific shooting.'