Funny observation..

A massive spot-light on the audience right side of the stage falls into the front rows, and people in the audience scramble to get out of the way. But the light remains turned-on. My first guess was that it was an accident during shooting, but I quickly decided it had to be intentional.

My favorite take on this is that the spot-light represents Weronika: the body has fallen, but the light = spirit stays on. Of course, the people in the audience get out of the way of the obvious physical danger of being crushed by the falling equipment; but Weronika herself has been ignoring obvious warning signs regarding her own physical health all along.

Also, the audience in the movie relates to us in the movie audience: how well are we paying attention ourselves to the physical dangers Weronika experiences? Like you (Glennb02), I also see some humor in this little event at the corner of the screen: it's as if the makers of the movie are peeling up the corner to wink at us.

There is a parallel to this in the part of the movie about Veronique. In his workshop, Fabbri reads her part of his novel, tells her he is thinking about naming it "The Double Life of ---", and says he hasn't decided yet what to call it. Like the stage light falling into the audience at Weronika's concert, this is also a wink that tries to draw us in the audience into pondering what is happening. I think that the question at this moment in the movie is this: Is Fabbri really describing Veronique's life, or is he just fabricating and manipulating her yet again? Does he have some supernatural insight into her life, or is he just (ab)using what she told him herself in the hotel room? (My take is that he's just fabricating again, as his name implies; but that Veronique maybe falls for his story.)