For Katie Holmes, show must go on after filing for divorce from Tom Cruise Katie's got backup - and she's not leaving home without it. Katie Holmes emerged from four days of seclusion in her Chelsea pad yesterday - her first public appearance since filing for divorce from Tom Cruise - surrounded by a pack of beefy security guards. She flexed the heavy muscle amid fears she's being stalked by Scientology officials because of her bombshell split from church member Cruise - and concerns he might try to kidnap their daughter, Suri, 6, sources told The Post. Holmes wore a blue button-down, long-sleeved dress but was missing a key accessory - her wedding ring. FIRST PHOTOS: Katie Holmes mobbed in NYC. She smiled faintly and cast her eyes down as she exited a black Mercedes-Benz sedan with Florida plates in front of 66 Seventh Ave. in Chelsea at about 9 a.m. She was there for a scheduled appearance on the reality-TV show "Project Runway: All Stars." Flanked by her crew of rent-a-cops, Holmes walked into Parsons The New School for Design, where the Lifetime show tapes. A judge on the show, Isaac Mizrahi, later said Holmes, 33, did a bang-up job despite her turmoil. "She did great," he told People. Another source added, "She was engaged, articulate and wonderful." Hours later, Holmes was spotted entering a Fifth Avenue office building. She arrived back at the $12,500-a-month Chelsea apartment she's renting for her and Suri at 3:25 p.m. A swarm of media followed her into the basement parking garage, where she stayed in the Benz's back seat. Cops showed up 25 minutes later and ordered the paparazzi out. Go to The Post for the full report.