Catchphrases have an expiration date. There’s just so many times you can laugh at “Where’s the Beef?” or “That’s What She Said.” Bruins general manager Peter Chiarelli, whose team will open its second-round playoff series against the New York Rangers tomorrow night at the Garden, has one he’s sick of, too. It’s one he’s heard a lot because his team finished the regular season in a 2-5-2 slump, then built a 3-1 series lead on Toronto in the first round. “There’s no flipping the switch,” Chiarelli said yesterday during a press conference less than 24 hours after his team’s miracle comeback from a 4-1 deficit in the third period of Game 7 against the Maple Leafs. “I know it’s a trendy headline, but the last few games prior to the season (ending), there were some good things that were coming. So that’s a trend. We saw strong periods in games, and we saw some periods where we weren’t so strong. You’ve got to look at last night, although it looked like a switch was flipped, there was a push. Like you can’t rely on that. You have to have those pushes to overcome deficits like that in the course of a playoff series. “Listen, we’d all like to have that type of 11 minutes, or I guess it was Game 5 the last period. Hey, I’d love to have that every period, every game. And I see people write about, well, that should be the Bruins every period. It’s not possible. You can’t physically play like that. So there’s no switch. Valid question, though. But there’s no switch. This is about focusing and getting to that level.” Going forward in the postseason, the Bruins might not be able to play at such a frenzied pace for 60 minutes. But there was a structure to the mayhem that might translate. In fact, maybe just three-quarters of that effort and execution of strategy could prevent the Bruins from facing three-goal deficits against the Rangers and others. “(Coach Claude Julien) did a good job in that last 11 minutes. He did a great job because the players have to generate the intensity, but you have to also, like if you just ran around like a chicken with your head cut off, you’re not going to accomplish anything,” Chiarelli said. “So that intensity, that desperation, but the composure to make the plays that they made . . . net-front traffic, that’s all we talked about this whole friggin’ series behind closed doors, net-front traffic. We saw that on the three goals (that tied and won the game).”