Your route between 51 and 50 must have taken you within 200m of 3. I don't think I would have found the motivation to do another 15k after finishing 50+k.
Was asking myself what is that guy doing, running on the paved road opposite direction from Camp Matatoc, at 7:10 PM.. Something to tell 'em grandkids at the fireplace ("... once upon a time there was a runner that finished but forgot to punch a low-point control ... ")