Am I missing something? 20 mile splits around 1:44-1:45 for the leaders? And a finish time of 2:13?
That mat must have been placed long, right?
The half splits give about a 5:02 pace...20 mile split is closer to a total pace of 5:15. The end result gives a final pace of 5:04.
They couldn't have slowed that much between 13 and 20, and then picked it up the last 10k. That would equate to 28+ for the final 10k.