Mike Woodson said earlier this week he wasn’t going to “panic” over the Knicks’ disappointing showing before the NBA All-Star break — when they lost three of their last four and looked mediocre for much of January and February. Well guess what? It’s time to panic. At the very least it’s time to make some changes to shake the Knicks out of a slump that certainly wasn’t cured by some time away from basketball. Woodson has to do something to wake up his group of “Dead Men Walking,” something to get them to play with urgency, energy and enthusiasm. The Knicks displayed none of that last night in losing to the Pacers 125-91 in a game where they embarrassed themselves for four quarters, looking nothing like a team with championship aspirations. “We didn’t show up,” is how Woodson surmised the loss. “They whipped our [butt] from beginning to end.” It was over after the first quarter, when the Knicks trailed 30-18 after going 0-for-7 from 3-point range and allowing the Pacers to shoot 61 percent from the field. By halftime the Pacers had built a stunning 74-44 lead. The second half looked like the Harlem Globetrotters playing the Washington Generals, as the Pacers, who were averaging fewer than 93 points per game coming in, led by as much as 39 and set a season-high for total points. “We just didn’t compete,” was a phrase said by several players in the Knicks’ solemn locker room. The Knicks looked as if they were playing with a weekend hangover, while the Pacers raced up and down the court, often finding easy layups and dunks. One sequence that summed up this debacle came just before halftime when on a missed shot Pacers forward Paul George grabbed a long offensive rebound near the free-throw line, slipped past a sluggish Knicks defense and exploded for a flying dunk with authority. As for the Knicks, they opened the third quarter with Carmelo Anthony missing a driving layup and Tyson Chandler blowing a point-blank follow. It didn’t get much better than that.