Yes I went the wrong way there too, was no-one in front and saw runners coming from even farther in the wrong direction, and I was leading a group of about 10 or 12 and we all went the wrong way, luckily a bit farther back someone knew where to go and corrected those behind, but obviously others went wrong later too, very confusing, my garmin recorded 13.3miles 
Still, it was a great day, sunshine too, shame about the headwinds, seemed to be always running into it, lol