Gordo - where's the lava?

Something struck me earlier when pondering the issue of Gordon Brown's alleged bullying of junior staff - especially the part of the story that is relatively undisputed, namely that he has a 'volcanic temper'. We take that fact as a given, because we've heard it from so many different sources over the years, but when I thought about it I realised that, oddly, I couldn't actually picture what Gordon Brown "erupting" might look like in reality. Over the years on television I've seen him glower, sulk, pout, and generally drone on relentlessly in speeches, but never actually explode. I suppose the lesson is that, perhaps surprisingly, it is actually possible for a person in the public eye to keep one of their key personality traits strategically hidden from view, even over a period of decades.