They poured off the train at Middlemore - Auckland high school students hyped with an attitude borrowed from gang culture on the other side of the world, about to go to "war".
They said they were representing one school, out hunting those in the distinctive colours of another.
The storm had been brewing for weeks - months even - with a war of insults and put-downs.
School fights aren't unusual. They happen every day, sometimes organised between students who know each other, punches traded often with school jerseys wrapped round their fists so they won't have to explain blood noses.
But this was different. In the clash outside an Auckland high school last weekend, one boy was stabbed in the stomach, another suffered a concussion.
Police Inspector Matt Srhoj said it was "incredibly fortunate" no one died in the incident.
Several days later, a fight across the Tasman had tragic consequences.
There, Solomone Taufeulungaki, 15, was allegedly set upon by a group of young people outside a shopping centre in Melbourne's west, and stabbed.
It's believed Taufeulungaki went to the same school as his attackers, and the attack was reportedly sparked by an argument, on social media.
Impact of social media
The Auckland school's board of trustees chairman, speaking to the Herald, was clear on one of the reasons behind the violence in his view.
"It's social media. They're using it as this vehicle to confront each other, and it just escalates."
Social media this week has been running hot with talk of retribution, and seemingly no sense of remorse.
Retribution is something schools and parents are moving swiftly to prevent.
The chairman said soon after the attack, the school, the old boys' network, and wider community rallied together to support their students.
On Monday, over 100 former students returned to the school. Some even flew in from out of town especially.
They each stood in front of the school and shared their own story, with messages around the importance of fighting "the good fight of faith and not fighting with violence".
The school had been working with other schools involved and police. Social workers were also providing a wrap-around service for affected students.
But there was only so much schools could do, the chairman said.
"We as parents need to be especially vigilant around our children, know where they are, who their friends are, and what they are doing on social media."
Social media-driven violence is not new.
In November last year, as many as 100 students from several schools descended on Mission Bay for a massive brawl, again organised through Instagram.
Students caught up in the alcohol-fuelled mayhem told the Herald then it was lucky nobody was killed.
Eight youths were eventually arrested, one for assault. One person was taken to hospital with minor injuries.
Increasing school assaults
According to the Ministry of Education, the number of stand-downs for violent incidents in schools has dramatically increased in recent years.
Stand-downs had been on a downward trend until 2015, when it jumped from 14,208 to 19,412 in 2018.
The number that involved either assault on other students or staff also jumped, from 4219 to 7415 over the same period.
In 2018 assaults on other students made up 32.3 per cent of stand-down incidents, and on staff 5.9 - up from 2.1 in 2015.
Auckland University Professor of Education Peter O'Connor said young men in New Zealand fighting was "nothing new", but recent societal pressures had amplified it.
"It must be scary as hell for young people today, looking at the world, trying to see their future in it, with climate change, rising inequality, fewer job opportunities."
Now on top of that all, Covid-19.
"We are all living in a time of heightened emotions and anxiety," O'Connor said.
"On top of that our young men are not being taught the skills or capacity to process those emotions and anger in meaningful ways, so in a sense this increase in violence is somewhat expected."
Not only was it violence towards others, O'Connor said self-harm, and youth suicide, were also on the increase.
Part of the problem was New Zealand's traditional idea of what it was to be a "man" - the tough rugby player who doesn't speak about his emotions, now with some gangster imagery borrowed from overseas playing into it too.
"We need to be countering that image with other stories, that it is OK to be soft and gentle and kind," O'Connor said. "Being a man does not mean being tough."
Thrown on top of it all was social media.
"When I was at school it was chants of 'Fight, fight, fight', but now it's happening on social media, and can happen 24 hours a day."
O'Connor said along with increasing capacity within the school system for "emotional education", parents, caregivers – any adult figures around these boys – needed to help model a healthier image of being a man.
Idolising gang culture
Parents of students spoken to by the Herald – all on the condition of anonymity for their children's safety – said they'd watched the bravado attitudes building in their children, copying this "American rubbish".
Gang signs, the way they walk, the way they talk, the gangster lyrics of rap songs they record about their schools, with their own unique names and videos.
Fights were "repped" on social media, with "likes" providing instant gratification.
But the violence had got to a point some parents weren't letting their children walk around outside school in the blazers.
"They're 'repping' their schools and their area. It's silly, they think it's America, that it's east versus west, versus south."
Parents needed to take more responsibility and check in how their children were doing, one parent said.