Killing yourself in the theatre can bring on strange atmospheres. Chekhov and Ibsen give it tragic absurdism, ambivalence even. Ben Brown's college professor in All Things Considered at Hampstead last year certainly exuded a certain uneasy gallows humour - something you feel David Rabe flirts with in this cross-cultural exchange from Connecticut's respected Long Wharf Theatre at Newhaven, but ultimately eliminates.

In A Question of Mercy Rabe revisits an area - euthanasia - dealt with by Robert Lepage in Seven Streams with harrowing gravity. Once again, we have a young man dying from Aids (Rabe's version is based on a short story by Richard Selzer), this time, looking for a doctor to help him out of the world and a small group of people upon whom the repercussions are investigated with the minute, ruthless logic of the everyday.

In other circumstances, this might have elicited a wild, surreal kind of humour that Rabe himself conjured in the very Gothic-hued Hurly Burly. But Doug Hughes's production opts for a safer realism following the legal implications and triangular emotional minefields existing between Anthony's lover, his lover's best (woman) friend and the doctor.

At odd moments, either from Seth Gilliam's Anthony or Richard Bekins's distraught, Henry Fonda-ish Thomas, you get hints of a sharper self-irony. But mostly this is a play about ''heart'' - and none the less affecting for that in a drama that ultimately overcomes reservations by the sheer honesty of its players and the oddly gripping rumination on the nature of fate, of how, as David Chandler's Dr Chapman ponders, the pain the moral journey of A Question of Mercy poses might have been avoided if he'd never answered the opening phone-call in the first place.

A Question of Mercy is at the Bush to May 23.