If you got caught up in some disruption in Century City and Beverly Hills today, it was just an evacuation drill. Some 6,000 workers in the twin, 44-story Century Plaza Towers were cleared out and moved to Roxbury Park in neighboring Beverly Hills. Mayor Jim Hahn—who is taking every opportunity to hang around the fire and police chiefs these days, figuring it has to help his reelection chances—declared the full-scale exercise a success.