There is a scene of introspection in Kim Bartley's beautiful documentary about John Joe Nevin that all but stings the eyes with its candour.
It concerns the boxer's recovery from two broken legs sustained in a family conflict last April, just two weeks after making his professional debut in Boston. Nevin pulls no punches in conveying the psychological war he had to wage with himself simply to survive.
Fearing his career to be over, John Joe reveals that - from the slew of empty days spent in a wheelchair - grew a dependence on alcohol.
The initial medical diagnosis was that one break particularly, a compound fracture of the right leg, was "a career-finishing injury".
So drink came to oil the hinges of his days and, with it, all ambition and responsibility seemed to curdle into a wistful past. Nevin spent his days in the pub, uninterested in climbing out from under its warm covers.
In 'John Joe: Reality Bites', to be screened on RTE 2 next Wednesday at 9pm, he takes the viewer, essentially, inside a confessional.
"It was very, very hard," reflects the Olympic silver medallist. "Boys would be going drinking, I wouldn't want to. Some days I'd go out and drink 7-Up, but they were all getting drunk at the end of the night. And they'd be all around my wheelchair, all plaguing me out.
"So it was either go on the drink and enjoy it with them or sit at home and be bored.
"You know if you're out, able to move around, you can go for a game of soccer, a game of pool, you can do things. You will occasionally drink, but not what I was doing. You know, going early in the morning, 12 o'clock in the day, coming back, going asleep. Getting up the next day again ... and straight away I'm off in my little wheelchair again.
"Sounds ridiculous, but it's the truth. Finishing up, it got a bit serious, it got a bit messy. It's not a nice place to be in, but it was a place that made me happy at the time. Because I wasn't thinking of the boxing, I wasn't thinking of anything. Just thinking of the next day, the next day and the next day.
"When I started to lose faith that I might never box, I didn't want to come out and let people see me in a wheelchair, because it's not me.
"This is why I had to start telling myself I'd be back. You know I made a wrong decision going on the drink, but in my eyes I had nothing else to look forward to. I just felt like I was useless."
Bartley's documentary follows Nevin from his pro debut in Boston last March through a convulsive eight months through to the redemptive homecoming in Dublin last November when, on a Matthew Macklin undercard, he delighted the crowd with a first-round knock-out.
In between, we get a sense of just how close he came to oblivion.
His legs were broken by a first cousin after John Joe had been asked to intervene in a family row. It meant that his career with Green Blood Racing in Philadelphia shuddered to a halt after just one pro fight, albeit he had already been struggling with homesickness while in America.
Nevin has always described himself as "a homebird" and there are times in the early filming when he looks to be pining for the comfort blanket of amateur boxing's High Performance programme.
His manager in America, Tom Moran, admits that John Joe is "thinking about when he's going home as soon as he gets here."
The leg breaks leave Nevin facing what his old coach Brian McKeown - with whom he has been since the age of 12 - says will be "the biggest battle of his life."
The trouble for Nevin is that his footwork, or what Billy Walsh describes as his "gift of movement", has always been what made him different. His destruction of a Cuban world champion in the London Olympics semi-final will forever stand as the most sublime essay of craft and elusiveness by an Irishman in a boxing ring.
Now, while out of action, his weight falls from 66 kilos to 59, all muscle definition in his legs disappearing.
Eventually, against advice, Nevin takes himself back to America, desperate to reclaim some purpose in his life. He is filmed having to abort a jog because it is too painful and admits during a gym exercise that he can feel the metal bar inserted in his right leg "coming up through the knee."
The impression is of a man desperate to pick up the scattered pieces of his career, self-pity supplanted by obstinacy. "It's hard when you're paranoid, when you're sickened with yourself," he says.
His is a story of survival worth seeing.