“Malkovich” says John Malkovich, in a key scene in Spike Jonze’s 1999 film Being John Malkovich. “Malkovich, Malkovich. Malkovich.” From the advance publicity, you might have been expecting something a bit like that tonight – a star-vehicle, with an organ recital tacked on. But from the moment you entered the hall – hung with totalitarian black and red banners – you realised that this was something very different.

This was no longer Symphony Hall, we learned, but the subterranean desert compound of the newly-deposed dictator Satur Diman Cha. A burst of gunfire later, and it was clear that he wasn’t as deposed as all that. With organist Martin Haselböck duct-taped to his instrument, journalist Caroline (Sophie von Kessel) was left alone with Malkovich’s gun-toting tyrant to capture what might be the last interview of both their lives.

There’s not much that a mere music critic can say about what followed, as Haselböck’s organ improvisations – electronically distorted to blood-curdling effect – wove fragments of Ives, Karg-Elert and the eternally-abused Ode to Joy into a thunderous counterpoint to Malkovich’s and Kessel’s stand-off. Malkovich delivered everything in an accented, mid-Atlantic monotone – whether Cha’s paranoid worldview, or his queasy fixation on mixed grills and anal penetration.

Kessel matched him with a superbly controlled portrayal of a woman using her professionalism as a shield against the unthinkable. And yet it was Malkovich - droning, ranting, declaiming - who pulled you inside his head, and in one extraordinary, barely-there moment of transformation from fugitive to bemedalled Generalissimo, showed a glimpse of this monster’s vulnerability. With these two magnetic central performances, plus Haselböck’s playing, you could almost overlook the heavy-handed twist at the end of Michael Sturminger’s script. Malkovich’s gift, paradoxically, is to make this whole compellingly horrible spectacle feel like a lot more than just a one-man show.