Go back to page 19. There seem to be three bandits running together with the doctor at the first photo point. I'll call them Mr. Red, Mr. White, and Ms. Grey. We don't know where that photo was taken, but the Three Banditos apparently ran 8:30ish pace, and the doctor is running with them at that point. He then manages to hit very even 5k splits at 6:30 pace, so it seems like he busted out some sub-5 pace in between that photo and the first chip mat, then went on to hit very consistent 6:30 pace until the finish. Then he doubles back and hands his bib to Ms. Grey. You can see that the three bandits finished together in about 1:51.
So yes, this doesn't prove anything besides bib swapping and aiding bandits, but it is very odd behavior. Who knows, maybe the guy really is capable of starting at 8:30 pace, running for a while, then accelerating to the point where he's able to hit the 5k mat averaging 6:30 pace. If that happened, I'm sure he shattered a few age group records along the way for the shorter distances.