When I consider the "decisive moment" in photography, I have to ask myself, "Would this have worked one second earlier or later?" If the answer is "no", then I'd consider that a decisive moment.

Assuming you consider that has some validity as a definition, what happens when you look at this picture and ask yourself the question?

I really like this image. I think the overall tone and darkness work really well. Your main subject walking into a vanishing in the center of the frame is very dramatic.

Here is what I think could be improved... I think the diffuse glow is overdone. Balancing the composition as far as the lights and darks go from left to right would really make this shot better.

I really like this one