No-one will be the slightest bit surprised by Brown's off-camera mutterings, which are entirely in 'character' - the dismay at meeting someone who disagreed with him, however mildly; the immediate finger-pointing and disloyalty towards his aides; the inappropriate use of language.
His usual response to this kind of set-back is to play the Macavity and disappear.
But he can't. The iron grid of his final-week campaign appointments, starting right away with the third debate and his need to prep for that, cannot be modified to the extent of giving him a few days out of the spotlight.
He will get grumpier and grumpier. The medication will be stepped up. The infelicities will multiply. The NuLab plotters will redouble their machinations. etc etc etc. Can even Mandelson recover this one ?
Oh dear, oh dear. It couldn't happen to a nicer chap.