The man, an intensive-care consultant by profession, was a medical assistant at the boxing, and revealed that he wanted to be a volunteer after treating victims of the 7 July 2005 bomb attacks. He said the Games had been a cathartic experience; after seeing the very worst of mankind, he was now in the midst of the very best.
It is a conversation that Coe says he will remember for the rest of his life, one of many of the often personal Olympic moments shared over those 17 days.
It's often tempting to make generalisations about the changing face of Britain (we've had 'Moody Britain' and 'Cool Britannia'). But the triumph of London 2012 is that it has held a mirror up to the nation and shown its true diversity and generosity of spirit.
The big question for marketers is where the shifting currents of Olympic glory will settle, and what the social legacy of the Games, which promised to 'inspire a generation', will be. For an industry that loves nothing more than a buzzword, the temptation to brand, package and sell the spirit of the Games is immense.
Alastair Macdonald, director of sponsorship insights at Havas Sport & Entertainment, says: '"Cool Britannia" was just air, a marketing exercise. This is something genuine.
It's not a marketing device or label like New Labour, it is something tangible happening to the country.'
London 2012 has shown that consumers truly value endeavour - a shift aptly summarised by a tweet from @mrjamesgraham during the Games: 'Almost a year ago to the day, London was on fire, and we were told "this is us". "Young multicultural Britain". Well, that wasn't us. This is.'
Nicola Clark is Marketing's head of features. Follow her on Twitter: @nickykc
THE UPSHOT - What brands should know about the Olympic effect
The end of winning at all costs
While the pressure on the British team has been immense, so has been the depth of appreciation of athletic endeavour. Winning was only part of the story. As Stefan Olander, vice-president of digital sport at Nike, says: 'The relentlessness you need as an athlete and the passion of athletic values will never grow old.'
Beyond 'Cool Britannia': Inspiring a nation
The Games have shifted the tone of voice of a cynical nation. Jamie Wynne-Morgan, managing director of M&C Saatchi Sport & Entertainment, says: 'The opening ceremony, from the Queen, Bean and Bond to the array of music, was a reminder that we may put ourselves down, but we are actually very good.'
The 'social Olympics'
While marketers have tired of endless declarations that this is the first 'social Olympics', much of the Olympic reaction has happened online: Twitter has fast become a 'global pub'. 'The thing about social media is that it is only a digital version of what people have been doing for years. The challenge for brands is not interrupting these conversations if they have nothing to say,' says David Peters, head of sponsorship at Carat.