The dad of a non-verbal autistic boy who vanished during a family day out has choked back tears while reliving the harrowing ordeal as his son's adorable request after being found was revealed.
Daniel Huxtable, 11, disappeared while visiting Sydney's Sea Life Aquarium with his grandparents in Darling Harbour on Tuesday.
NSW Police launched a large-scale search across Sydney which involved Polair, a geo-targeted SMS campaign, reviewing CCTV and tracking the location of Daniel's iPad.
Amid fears he may have fallen into the harbour, Daniel was found safe and sound on north shore line train at St Leonards several hours later, not far from his northern beaches home.
Relieved parents David and Alison were still emotional while recalling the nightmare on Wednesday morning.
Daniel Huxtable was reunited with his parents hours after he went missing during a family day out in Darling Harbour on Tuesday
I'm actually just choking up again to be honest,' Mr Huxtable told the Today show.
'I got the call and sort of just headed down to the aquarium.
'I was holding it together OK but then the few times that we were asked to describe what he was wearing to a few people, it all just started to become real and at that point it really took hold. So, yeah, it was terrifying.
'You feel hapless and helpless.'
His wife added: 'There's no words to describe the relief after the mental exhaustion and everything that we went through.
The aquarium and Darling Harbour precinct was at the time packed with hundreds of families enjoying the school holidays.
While his parents were frantic with worry, Daniel was unfazed about his time alone, walking and catching trains across the city.
David and Alison Huxtable (pictured with their daughters) described son Daniel's disappearance as the scariest days of their lives
All he wanted was a bowl of ice-cream and to go to the beach with his dad when he got home, according to mum Alison.
The next morning, he was jumping on the trampoline, oblivious to the panic caused hours earlier.
'If you saw a neurotypical child without mum and dad they'd clearly be distressed, ask for help but Danny was just having a regular day,' Ms Huxtable said.
'He was walking with purpose and looked like he knew where he was going.
'That's why no-one stopped to check. He looked like he was where he was supposed to be. We're so grateful that he was found.'
Polair was deployed during the large-scale search amid fears the non-verbal autistic boy had fallen into the water at Darling Harbour
Police made 51 decisions during their extensive search with resources stretched everywhere between the CBD and Hornsby.
'In essence, we followed CCTV, PolAir was up, the public were good after the message went out, we were able to get information from that,' Inspector Wayne Ashworth said.
'Luckily Daniel was just riding up and down on the trains,'