You are right; it was a handheld grab shot. I would have liked to use my SB-700 flash or grab her and say "hey, move over there in more light". But, when a woman is carrying a big sword and is in the middle of demonstrating a sword fight, it could be detrimental to my health.
Your FX (D800e) dynamic range comparison/capabilities were just what I needed. If the original results are even close to a FX camera then my quest for a substantially better dynamic range is futile. I'll just concentrate on using the tips you and others have provided.