Elle creative director Joe Zee needed extra security after a participant on his Sundance Channel reality show “All on the Line,” flipped out following his criticism. Zee acts as mentor to up-and-coming fashion designers. On last night’s taped episode, Zee advised designer Gemma Kahng to part ways with her friend and creative director David Victor Rose. After Kahng dismissed Rose, he sent hundreds of angry e-mails to Zee and to producers that were “so troubling,” the show hired security to accompany Zee on set and to Elle’s offices, sources said. “He would send about 25 text messages a day after I fired him,” Kahng told us, adding that Rose blamed the show for making her fire him. “He would send e-mails to Joe and the producers threatening to kill himself.” Sundance sources confirmed the incidents. Rose admits to “completely freaking out,” but says Zee unfairly characterized him as a grifter using Kahng for money, and didn’t fully research his contributions to her company. Rose said he’s seeing a therapist and making amends with Kahng.