It's not often you're briefed before a performance to shout “escape” should you feel the need for an instant exit (although I can think of several recent productions where such an option would have been welcome).

But in truth only the most faint-hearted of souls would wish to step off this delightful ghost train of a show, staged in the LEB Building as part of the Barbican's 101 things to do this summer season. Yes, it does require a certain amount of chutzpah, and I can imagine that for some the level of participation required could be a bit overwhelming; but for show-offs like myself it's a dream.

I don't want to give too much away about what's involved in the latest incarnation of this bizarrely-titled show that's been in constant development since 2004. A representative beforehand simply assured me that it's “bigger than ever”, and that would seem about right.

It consists of a solo 45-minute wheelchair-bound odyssey through a series of rooms ranging from the surreal to the frighteningly realistic, and requires constant improvisation on the part of the audience member, placing you at the central focus of every scene. For those unschooled in the ways of 'one-on-one' theatre, it's a thrilling introduction. A large cast ensures that each experience is wholly independent, every face is fresh and every journey unique.

All told, it's an impressively rendered ride that put me in mind of Ontroerend Goed's The Smile Off Your Face (which also used the wheelchair technique). However, unlike that experience there is nothing especially personal or challenging here. Never are you really tested or questioned - dare I say it feels a little sanitised.

There are several occasions when scenes threaten to become more testing than they actually turn out to be, morphing into something altogether more cosy. I felt let off the hook at times, and it wasn't until I reached the truly harrowing climax that I even considered shouting “escape”.