Law & Order: SVU is tackling post traumatic stress disorder. In Wednesday’s hour, Once Upon a Time alum Eion Bailey plays Frank Patterson, an Iraq war veteran with PTSD who becomes a key witness in an investigation of a sexual assault in a nightclub. The role was “years” in the making, says Bailey — who credits his experience filming HBO’s Band of Brothers as the catalyst for his interest in U.S. soldiers. In fact, the writers had been toying with doing an episode like this since last October.