Possible, I thought so at first too but looking at it for awhile that just doesn't seem possible unless its not the stock nerve blue. I used to own 3 nerves, two in the traditional SP blue. I looked at my old pix and sure the ones with flash are a different shade, but they don't look team. I'm thinking it may be a teal nerve that looks blue without proper light?
also he could have tried touching it up in Adobe Lightroom, and the one with the flash had a higher saturation to begin with so playing with color balance made it look teal.
I'm not sure, but I've seen flashes do a lot (and I'm more of a photographer then a paintballer, photo is my first and primary hobby) but unless it was a real strange one I cant see it making the stock SP blue look that Teal.