You can't just carry a sword around as an empty threat. You shouldn't draw it, or keep it drawn, unless you intend to kill someone. Hiro runs toward The Enforcer, raising the katana to strike. The Enforcer does the proper thing, namely, gets the hell out of his way. The silver ribbon of the katana shines up above the crowd. It attracts Enforcers and repels everyone else, so as Hiro runs down the center of the Towne Hall, he has no one in front of him and many shiny dark creatures behind him.