Tuukka Rask didn’t even want to talk about what happened to the Bruins in the playoffs three years ago. The reference of the postgame question at the Air Canada Centre last night was, of course, to the B’s blowing a 3-0 lead in the 2010 Eastern Conference semifinal series, as they dropped four successive games to the Philadelphia Flyers — with Rask & Co. unable to win Game 7 at the Garden despite taking a 3-0 lead in the game. It’s a fair bet that historically devastating outcome will be on the minds of many at the Garden tonight, where the Bruins — now even with Toronto, 3-3, after losing Game 6 of their quarterfinal series last night, 2-1 — face a do-or-die match against the high-energy, overachieving Leafs. The Bruins have wasted two chances to put away the youngest team in the league and the least experienced in the playoffs. And as they face another Game 7 at the Garden, a loss will be viewed as maybe not quite as appalling as that Philly series, but close. For the Bruins, so erratic all season, to find themselves in this predicament can be blamed on many players whose execution and/or compete level has been well below par. Rask is not one of them. “Tuukka was awesome, just like every game,” defenseman Dennis Seidenberg said. “He does that every night. You can’t ask for anything more from him. If you only score one goal, a lot of times you end up on the wrong side.” Alone among the Bruins, Rask has been at his very best in this series. If each of his teammates had performed as well, this series would have been over before last night. But Rask can only stop pucks at one end of the rink, not score them at the other.