"When you actually think about what could have happened, it makes you feel sick," the father said, adding that he views the mishap as a gross violation of health and safety standards. "My boy could have been killed."
Collinson said he wasn't initially told how long his son was away from the centre or where the boy was found, but he's incredibly grateful to a truck driver who he understands spotted the boy and took him to the centre - the closest one he could see - before calling police.
The father said he wants to find out who the stranger is so he can thank him.
"The truck driver called police because he has children - he wasn't happy about it," Collinson said he was told. "He's done us a really big favour."
Centre director Nicki Mafi declined to comment when approached by the Herald.
"We do take the matter very seriously and we need to do a thorough investigation," she said, threatening legal action if she or the centre were mentioned by name.
Isabel Evans, the Ministry of Education's leader for Auckland, said early childhood education services are required to notify the ministry when they notify other agencies - such as WorkSafe, police or Oranga Tamariki - about serious incidents.
"We were advised of the incident today, and have requested the centre for its incident report and investigation notes to inform the ministry's investigation," she said on Monday.
Of the nation's more than 4600 licensed early learning services, there were 10 complaints filed in 2019 - the most recent reporting year - regarding "allegations of children accidentally leaving a service due to unsecure premises or a lapse in staff supervision", according to the Ministry of Education. Eight of the complaints were upheld.
Collinson said staff initially suggested that another parent must have accidentally left both gates at the centre open. But, he said, they'd now told him his son somehow left through a door in the back area of the facility that should have been locked.
When a teacher realised the child was gone, she ran outside screaming for him but the truck driver arrived with the child soon thereafter, the parents were told.
Collinson questioned whether he and the boy's mother had been given the full story.
"That's what's annoying," said the father of five, adding that "nothing like this has ever happened before" at the roughly 20 daycares his children have attended over the years.
It's something that shouldn't happen and people should know about it," he said on Sunday, adding that he was worried other parents at the centre might not have yet been told about the incident.
Luckily, he said, his son doesn't seem to understand the gravity of what happened and the danger he potentially could have been in. Regardless, he said, his son won't be returning to the facility even though he had made strong connections with the teachers there.
Collinson said he doesn't necessarily want the daycare shut down, but there should be a formal investigation.
"I want to make sure nothing like this ever happens again."
