Declan wanted to celebrate the incredible news that he was finally in remission from leukemia with a bang - literally.
His biggest wish after spending 60 days in hospital was to go beyond his comfort zone and "blow stuff up".
So the 12-year-old travelled from Sydney to Canberra on the weekend with the Make-A-Wish foundation for a behind the scenes experience with frontline AFP officers.
His eventful day began with being greeted at the Majura headquarters by an extravagant motorcade.
Officers then organised a staged hostage scenario with the personal response group, took him in an armoured car to the training village where he was involved in breaching exercises, and gave him a taste of water policing.
"They gave us a charge and you had to pull the pin and hit the top of it and hid behind doors and [the brick wall] blew up," Declan said about the breaching exercises.
By the end of the day he had met Prime Minister Malcolm Turnbull, Governor-General Sir Peter Cosgrove and the AFP Commissioner Andrew Colvin.
Declan's mum Belinda said the whole family benefited from the experience, which became the light at the end of a tunnel filled with seven months of chemotherapy and more than 30 blood transfusions.
The AFP would not provide Declan's or Belinda's last name.
"We have been looking forward to this wish for many months and it has been a great distraction from what is like a big wrecking ball hanging over our family while he was still receiving treatment," Belinda said.
"The memories and experience will never be forgotten and we want to make sure that everyone involved knows how much we appreciate everything that happened in the lead up to the wish and on the weekend."
Sergeant Peter Murphy from the specialist response group said the surprise Declan got when he heard the loud explosion was priceless, as was his excitement at the various tasks.
"I don't think he knew what to expect, and neither did the family," he said.
"It was great to get the opportunity to help out a family going through a tough time and give them a distraction for the weekend."