An alternative title might be: "Three Failed Revolutions and a Plane Crash" and with its juxtaposition of the Tienanmen Square massacre, something like the Anders Breivik murders in Norway, and a story of how the leaders of a revolution turn into the dictators they have deposed, it might be just about the most zeitgeist-throttling piece on the Fringe – a head-on collision between Chimerica and The Events in an all too recognisable political and globalised landscape.

Actually, the similarity between Thorpe and Greig's Breivik-analogs is startling, both pin-pointing what makes him such a worrying figure is that he is almost a weaponised, psychotic end-point for liberal anxieties about hardline Islam's misogyny. By contrast, Thorpe's take on the man immortalised standing in front of a tank in China in 1989 is infinitely more significant than Kirkwood's Hollywoodised version.

Rather than giving him an emotional back-story, Thorpe looks into a void valorised. As well as compellingly telling a story, Thorpe cannot help asking more questions than he answers. The surprising juxtapositions between the four situations, and the effect in the choric speaking of the final segment (whose subject I won't spoiler), intelligently build into an intricate interrogation of human behaviour.

In Sam Pritchard's production (which I first saw previewed at Latitude) we also focus intently on human speech. The performers are seated and mic'd. Although at first they seem deadpan, there are subtle shifts, emotional patterns and traces of accents to the softly spoken, loudly amplified voices – almost like, as small creatures under microscopes, we are inspecting this component by means of magnification.

As the production draws on, the lights slowly, imperceptibly go up on the audience, so that by the close we are as brightly lit as the performers. There is a direct challenge in this: "we're not just talking hypothetically," the production seems to say. "You can't just sit there and listen to all this; you have to make decisions too; hopefully what we've just said might help you think about those a bit."

From electrifying writing and performances to serious ethical confrontation in one hour. There Has Possibly Been An Incident is both profoundly satisfying and deeply unsettling at once.

- Andrew Haydon

There Has Possibly Been An Incident continues at Northern Stage at St Stephen's until 24 August (not 9, 12, 19)