The £1 million, 45ft stage has three revolves and 17 lifts. Another audience member said: "There's so much machinery on stage, which is in semi-gloom for much of the time, that it's not altogether surprising that someone has been injured like this." After several glitches with the set in Toronto, where the show was first staged, actors in London were made to rehearse "flat-floor" versions of all the battles.