I don't feel entirely comfortable reviewing An Instinct For Kindness. Chris Larner's deeply moving one-man-show, retelling his trip with his ex-wife to Dignitas, the clinic for assisted suicides, somehow seems too personal to critique. It is a man recounting in vivid and harrowing detail the hardest experience of his life. Who am I to say how well he’s done it? But however difficult it is to review, it must have been exponentially harder to write and even worse to perform. For this alone it deserves praise - and it's also a great piece of theatre.Both Larner's writing and his performance are magnificent. The beginning of the show is in the most natural of language, sacrificing in fact some of the inventiveness and imagination we later learn Larner is capable of, in favour of straightforward delivery and patter not of an experienced writer, but of an ordinary man reciting a difficult but oft-told anecdote. Larner acts as both first-person narrator and as every character in the story – his ex-wife Allyson with her wonderful, cynical humour; various family members; and even the Swiss doctors and nurses who attend to them. Each character is beautifully imagined in their environments, seamlessly implying whole dialogues through the reactions of only one party. It is probably one of the best performances by a single actor at this year's Fringe.The play, however, has set itself a limit that places a glass ceiling over its aspirations. In order to treat its topic well, it does not let itself be too experimental, nor does it let it lift itself to dizzy new theatrical heights. It just tells us things straight. It takes a topic that should involve us and move us, and treats it as we'd expect. This is by no means a problem or a failure, but it is a limitation – the thing that makes this a four-, rather than a five-, star show. I went into the theatre thinking that assisted suicide was a sad but sometimes necessary thing, and I left thinking just that, having learnt very little.But this limitation is entirely appropriate: the ending, death, is inevitable, as is bereavement – there are no surprises or final flourishes, just a full stop. It doesn't need, or particularly want, to be a five-star show – it wants to tell a story. 'I want weeping,' says Allyson as she describes her funeral, 'I want wailing, I want people to be incon-friggin-solable.' Chris Larner gives her just that – it is everything it needs to be.