The big deal is that run isn't supposed to matter. The format of the comp is the best run wins, not the best average. Its designed that way so you can go out and lay it all on the line, and if you fall you have another chance. If the other runs mattered, people would be much more conservative, and it would be less fun to watch.
Its just the prelims anyway, one extra rider in the finals won't make much of a difference and its also more exciting to watch. They could have even had a playoff between the two.