BALTIMORE — When you’ve lost more than half the games you’ve played on the road this season, and had won just one road series, even if it did come against one of the better teams in baseball in the New York Mets, it’s clear that victory will never be simple or a given, regardless of opponent. But as difficult as they made it on themselves early in the game, the Mariners persevered through mistakes, a blown three-run lead and memories of past failures to pick up a 7-6 victory in 10 innings over the Baltimore Orioles in a four-hour marathon on Thursday. Diego Castillo gave one of his best pitchi…