Every January, as temperatures plummet, New York's Public Theater opens its doors to Under the Radar, a festival that features cutting-edge theater from around the world. [...] This year, Under the Radar is presenting work from Chile, Japan, France, Canada, Rwanda — and Brooklyn, N.Y. In a rehearsal studio in the borough's Park Slope neighborhood, a company called 600 HIGHWAYMEN is rehearsing its new show, Employee of the Year.