Dracula West End 28/04 mid show stoppage

I was at the 28th April evening show of Dracula and we were right at the end, the climax of them finding and killing Dracula and all of a sudden she stopped talking all of the crew came onto the stage around Cynthia and draped her in a black cloak (I thought it was all part of it, cloak and all) and the safety curtain came down.

I don't know if it was to do with it, but she stepped onto a step and onto the coffin, the step moved a small bit when she got on the coffin but she didn't slip or fall, so I didn't think that was big enough to stop a whole West End show, so much assume it's something else entirely?

If it's that, well I can't really believe it as a retired dancer, the show always goes on even if you're injured, you carry on!

Anyone heard anything?