Having taken a deep breath, the 23-year-old has become submerged in the particulars of a performance in Montreal's Parc Jean Drapeau Aquatic Complex in August, where he competed in the 100m breaststroke during the IPC World Championships.
His final race is recounted as though in real-time, his proficiency in the pool so established that the Scot is not inclined to break his rhythm despite acknowledging that he has left his audience floundering somewhere in the shallow end. Once caught up, it transpires that the Edinburgh-born swimmer missed out on a medal narrowly after finishing in fifth place overall.
That statistic is sufficient to understand that bronze was kept from his grasp, but Quin's distance from a medal is more accurately measured in time; touching the wall just 0.2 seconds behind third-place Artem Pavlenko of Russia. It is instructive of the capriciousness of professional sport that such gossamer margins can separate success from disappointment. But Quin has not allowed himself to become saturated in frustration, instead pulling himself out of the pool with a broad smile and a cause for celebration.
"I broke my own British record and PBd; that's the way forward for me," he says. "My time was 1:08.81, which is, what, a ninth of a second faster [than his previous PB]."
Such a disposition can be disarming, but Quin is practised in the unexpected. A celebrated member of the Warrender Swimming Club, there was a time when it was not just improving his propulsion in the pool which was a challenge for the youngster. By the time he had reached 16, Quin had to be helped from his bed each morning as arthritis took hold, while he also suffered from the effects of Crouzon syndrome - a disease which affected the growth of his skull and led to learning difficulties - as well as tunnel vision.
One's first meeting with a paralympic athlete can seem like an occasion to tread carefully, yet that timidity is denuded immediately by Quin. His assertiveness is witnessed the moment he plunges into competition, while his garrulous nature on dry land is such that members of his sport's governing body know better than to attempt to cut him off in order to wrangle him into a Team Scotland polo shirt as part of a photo-shoot ahead of next year's Commonwealth Games. The contest will comprise the largest assortment of paralympic medal events - numbering 22 in total - including six in Edinburgh's Royal Commonwealth Pool.
"We are all buzzing to make it; it's not very often that you get to represent a country like Scotland," says Quin. "You stand with the British team and hear them singing the national anthem, but being Scottish, you don't really want to sing [God Save the Queen]. You sing, but inside you are really thinking 'I'm Scottish . . .' We have a bit of fun with it that way.
"I've got the World Championships in Glasgow in 2015 too, so, if I don't make it to the Commys, then I'll have another chance to compete in Scotland a year later."
It is a statement made by way of instruction only, since Quin does not intend to miss out on the opportunity to compete in Glasgow. That is informed by his absence from the London Games last year - "Unfortunately, I had that disappointment, so to make the Commys would be awesome" - but also the challenge of honing his abilities to suit a competition which will not comprise his favoured breaststroke event.
"In my disability classification [S14] we've only got one event in Glasgow, the men's 200m freestyle," he says, albeit with little discernible contention. "I'm not a freestyler, so it's back to basics to try and learn the technique of the stroke again."
Finishing in seventh place in the 200m freestyle event at the British Championships earlier this year suggests he is not quite a fish out of water, while his efforts to grow more comfortable in the stroke will be aided by similarly renowned team-mates. Joining Warrender has allowed Quin to train alongside compatriot Craig Benson, a prodigious swimmer who reached new depths last summer when he competed in London. The pair are kept apart in competition but shared sessions in between have proven to be of certain benefit to Quin.
"The best thing about being a disability athlete is that I get to swim with able-bodied swimmers in training, so I am almost using them to push me to go faster and faster and faster," he says. "I train with Craig and he is a sporting hero; he is a role model, but he's someone I get to train with every day too."