"I ran out of luck," he says, shrugging. "I was caught carrying a bomb, which wrecked my legs. It happens. If you take too many chances eventually you fall foul of it and that was my time."
It was in 1996. The Glaswegian was serving in Northern Ireland as part of a police anti-terrorism unit, a battalion of hard men doing a hard job. Death and destruction were their daily diet. "I remember one of my friends from the firm telling me afterwards I frightened the hell out of a lot of those guys because I had this 1000m stare, a deathwish. I would go through a door looking for a gunman and thought I would avoid the bullets. It was then that it clicked that I needed help."
Maguire, now 56 and one of Scotland's most prominent archers, describes that moment as like having his legs cut away from under him. He collapsed in a corner, crying uncontrollably. A man whose whole life was disciplined and programmed dissolved into a gibbering idiot. What had become increasingly apparent to those around him, those who were in 'the firm', had finally become clear to Maguire. He was suffering from post-traumatic stress disorder.
The accident itself wasn't the cause; the illness had stalked him for several years before that, even if Maguire refused to acknowledge the symptoms at the time, an accumulation of sights and sounds from his tours gathering in his consciousness in preparation for someone to press play. "It's a weird effect, like watching a dvd over and over," he explains. "I'm not a maniac running about with a big axe; I'm a guy who has, effectively, got BBC1 stuck in his head with nothing but repeats showing.
"We call it unfinished business. It's just a little guy sitting on your shoulder waiting to jump in during a quiet moment. A flashback will pop into my mind and I'll wonder what I might have done differently. It can happen to anyone; you don't need to have seen a horrific incident and you don't have to shove pills down your throat, you just need someone to tap you on the arm and you'll be back online."
That Maguire is able to make something that has plagued him for two decades sound like little more than a minor inconvenience is indicative of how far he has come since first attending Hollybush House, a care home in Ayr that provides specialist mental health services for veterans. Unable to even admit to having PTSD for the best part of a year, discovering he was not alone and gaining an understanding of the condition helped, even if it is still a daily struggle to leave home in Ochiltree and be around people.
His immersion in archery, then, is all the more remarkable. It is almost five years since Maguire alighted upon the sport as a way to help his concentration, which had been so ravaged by his illness that it once took him 13 months to read a paperback. At the time he was "in no-man's land" but watched his children being shown how to use a bow and arrow while on holiday and began to consider the benefits of a discipline demanding many of the skills honed in the armed forces.
"I read up on it and bought a bow but after smashing a dozen arrows into the wall of the house I reckoned I could use a bit of help and went to a club," he says. "I was reluctant to be around people at first but I was blindly pulled into a competition; I remember looking like a Daz advert with my bright white trousers . . . all I needed was a colostomy bag."
Before long, though, the hitherto clinical marksman had mastered a compound bow and been introduced to Alistair Whitingham, a sports psychologist from Edinburgh University, who became his coach. Now, despite needing a chair to move around and a stick for balance, Maguire shoots most days as well as honing his fitness in the pool and with weight sessions, a level of dedication that took him to the brink of Paralympic selection only for an administrative oversight involving his classification to preclude his participation.
That disappointment has not dented his desire, perhaps because archery gives him more than simply sporting success. "It's a therapy and an esteem thing because it has allowed me to identify something I can still do," he explains. "I used to be a leader of men, programming complicated operations, but PTSD has a great way of deflating you and telling you that you're not worth anything. But now I can come away from a session thinking 'I can do this' and do it against able-bodied people, too, because the only two people in Scotland I haven't beat yet are my coach and the No.1 ranked archer in the country. All I need now is a sugar mummy to look after me because when you get to this level it's expensive."
Maguire is looking to Rio now but he concedes there were times that he could barely see beyond the end of the day. Suicide was something he considered. "There were times when I could have terminated, quite easily," he says. "I thought about it a number of times. The thing that stopped me wasn't thinking about other people; I was selfish and I felt I would have let myself down if I'd taken the easy way out. That was the cowards way and I'd never backed down from anything before but this was an invisible enemy that I could never track.
Looking back, does he recognise that guy? Can he empathise with him? "Yeah, but I don't think I like him. He was so clinical. Even now, I don't get emotional about death because I have seen so much of it; I get more emotional about my pets dying and I lost my wolfhound a few days ago. Maybe it is the way I was trained, I don't know, but it's a very deep mine to dig.
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