Boston College baseball’s NCAA Tournament action opened in Athens on Friday afternoon, and it looked like the kind of day that gets a team into the winner’s bracket. Then the ninth inning happened. Liberty scored twice off a tying groundout and a fielder’s choice that BC couldn’t turn, and the Flames walked off with a 4-3 win that drops Birdball into an elimination game on Saturday. This one is going to sting for a while. BC had the lead.