CCTV footage showed Bain arriving at the car park at 12.45pm on March 13 this year.
He parked at a staff allocated vehicle space, at 1pm, before getting out and leaving the girl inside.
About 2pm, a staff member saw the girl crying inside the vehicle. A security guard approached the car and saw the victim sitting in the driver's seat crying.
He tried to open the door but it was locked and asked other staff if anybody owned the car.
About 2.17pm, security returned to the vehicle and found the victim lying down on the centre console.
At this point concerns were raised about the victim's wellbeing.
He returned to the security office, before another guard went there in an attempt to get the girl out.
At 2.41pm the victim was successfully removed through an unlocked rear door, her body "wet from sweat".
She was taken to the reception area of Discovery Media where she was given food and water.
Bain returned to the vehicle at 3.02pm.
The vehicle's windows were wound down about 2.5cm and the victim did not need any medical assistance.
Bain told Open Justice what happened wasn't a reflection of who he was - he was a responsible, loving guy.
He said he and the child spent the day before at a 4-year-old's birthday party which turned into a big night.
He woke up the next day with a sore lower back, thought he'd stop to get a massage and ended up falling asleep.
"While I was in there I was so knackered that I fell asleep. They woke me up and said 'There's been a car alarm going off'. I'm like 'oh f***'."
He ran to his ute only to find the girl wasn't inside.
"I'm just walking around my ute going 'What's happened, has she been abducted?"
A police officer then appeared and told him she had the girl.
"I've never been so happy to see a police officer in my life."
He disputed court documents that stated he'd only left the windows down 2.5cm, instead said it was more than 5cm, enough for a person to get their arm in and open the door.
In court, Bain's counsel Mark Sturm asked the judge to sentence his client immediately as each day he was away from his construction business was costing him money.
He was currently working on a job in Waihi and was "suffering financially and is aware that he has brought that on himself".
"It's certainly not the defendant's finest hour. He's very remorseful and a lot wiser now in hindsight on what he should have done on the day.
"The defendant was feeling physically a little unwell on the day and needed some pick-me-up."
He had been visiting Auckland overnight with the girl and knowing that she was a sound sleeper he made the decision to leave her in the car and get a massage.
"It was a therapeutic massage ... and he thought it would be okay to leave [her] for essentially an hour in the car when she was asleep with the windows down so that the child could get some air."
'The risk was contained - lawyer'
Sturm said there were some delays with the appointment and Bain ultimately fell asleep.
"The time extended a little beyond what he was hoping for and when he got back he discovered there was a commotion."
Sturm said he accepted there was a risk put to the girl "but it was a contained risk as she wasn't going to be left there for a prolonged period of time".
He asked Judge Menzies to hand down a sentence of coming up if called upon - if an offender reoffends, however that was rejected.
"The problem I have about this is there seems to be an element of justification for the behaviour and that it wasn't their fault and I see that as a problem," the judge told Sturm.
After consulting with his client, Sturm said a supervision sentence would be accepted.
'Quite clearly you put her welfare at risk - judge'
"I'm not sure what circumstances suggest that that arrangement was an acceptable one for a 3-year-old child," Judge Menzies told Bain.
"Quite clearly you were putting her welfare at risk."
As for his excuse that he was longer than expected, Judge Menzies said he was still planning on leaving her alone for an hour.
"It turned out to be double that ... As I said to Mr Sturm, I'm getting a sense of downplaying the gravity in terms of the provision and I'm not entirely sure that you do recognise the seriousness of that particular conduct," he told Bain.
He sentenced him to 12 months' supervision along with a special condition that he attend an assessment and complete any parenting programme as determined by probation.
