You sometimes get wild lighting at rock (or in this case psychedelic soul) concerts, It usually messes up all automatic measure of exposure because between the moment you measure and the moment you shoot the lights change drastically.
Occasionally though, that results in very interesting (although unpredictable shots). I was astounded to discover this photo after the Monophonics concert I attended in Paris in early October. I didn't remember shooting it like that. And I love it.