The mother of one of the children, Skyla, told the ABC the incident was her worst nightmare and she was grateful for the quick actions of strangers who saved her daughter.
"She got out through the back gate, she went walking down on Foxwell Road where the main road is," Amelia Finney said. "She was seconds away – she went to take a step off the gutter to try and go onto the road."
On Monday, the company which runs the centre, Okeedokee Kids Pty Ltd, was found guilty of four charges and fined $15,600 over the incident.
The charges included failing to adequately supervise children, failing to protect children from harm, failing to ensure policies and procedures are followed and for children leaving an education service premises.
The first two charges each resulted in a fine of $7500, while the latter charges brought fines of $300 each.
In a statement, the Queensland Department of Education – which took legal action against the service – said it welcomed the penalties imposed and that they reflected the seriousness of the offences.
"The prosecution sends a strong message to all approved providers about their responsibilities to closely supervise and protect the children in their care from risk of harm," the statement said.
"In particular, the magistrate noted there is a high level of trust placed in a service by parents, and this incident could have resulted in death or serious injury.
"In setting the fine, the magistrate considered the defendant's remorse, co-operation with the regulatory authority and its prompt response to the incident.
"It is critical that everyone involved in the provision of education and care to children is aware of the importance of active supervision, and this case shows the serious consequences that can result when children are not adequately supervised."
A department spokesman said supervision policies and procedures were its priority due to the risk of harm to children if not complied with.
"The department will continue to work with the early childhood education and care sector to promote active supervision, protect children from harm, and ensure governance arrangements are sufficient," he said.
"Where the steps taken by providers are inadequate, the department will not hesitate to take appropriate action."