Late-night voices raised in anger, drunkenness or fear rarely disturb Caleb Jones. He has learned to sleep through horror, porn and hip hop. Not even breaking bottles, barking dogs, howling alarms, slamming doors or squealing tyres can wake him. The rhythm of the police helicopter is the soundtrack to his dreams.
But he cannot sleep through the sound of this night. It scares him more than the things he did earlier, when he stood on a platform eight metres from the ground. "I want you to take hold of the rope above your head and place your right foot on the cable," said Jackie, our instructor. Caleb, who has trust issues, baulked, but Jackie remained unruffled. "You can do it," she insisted.
With Team Hedgehog behind him, urging him on, he took a tentative leap of faith. One foot felt its way on to the cable, followed by the other. Gripping the rope tightly, he eased himself out over the dizzying drop.
His crisis of confidence came a quarter of the way along. Suddenly, Caleb's faith disappeared from under him and he fell.
He didn't fall far - the safety harness dug into his thighs. For a moment, he dangled in mid air, scrabbling for purchase. Then his feet regained the cable and his hand grabbed the rope. He completed the rest of the course so quickly we renamed him Indiana Jones.
We are staying at an outdoor education centre near Bakewell in Derbyshire. Before bedtime, Caleb has crouched inside the den he helped to build in the forest. He has crawled through underground tunnels to escape a giant child-eating spider. He has completed an obstacle course through the Amazon. And after dark, he followed a rope that wound mysteriously through bear-infested woods.
Team Hedgehog accept Caleb's learning and behavioural difficulties and support him in every way they can. But by bedtime, tiredness has set in and tempers are fraying. "The rest of Team Hedgehog do not want you to throw your dirty socks at them, whip them with your towel or pull their duvets off and stuff them through the window," I explain to Caleb. It is my umpteenth visit to his dormitory.
Undertaking challenging activities and working as a team, being away from home for a few nights and sharing a room with other children are key aspects of the residential experience. Often it can be a lot more demanding than balancing on a cable eight metres above ground.
After lengthy negotiations, the rules and boundaries of bedtime behaviour are re-established and I return to my book and chair just outside the dormitory door. Ten minutes pass and most of the children have settled down. One by one, their whispers die out and they drift off to sleep. Soon it is silent. Well, almost silent.
I put my ear against the door. Someone is sobbing. I creep inside with my torch and find Caleb awake. "What's the matter?" I whisper.
"I don't like the noise," he says.
Beyond the gentle breathing of Team Hedgehog, there is only silence.
"There isn't any noise," I tell him.
"That's what I don't like," he replies.
Steve Eddison teaches at Arbourthorne Community Primary School in Sheffield, England.