Aw, I much prefer your version of "going postal". The only thing I'd ever heard is when a highly disgruntled worker goes to his place of work and bombs or shoots, killing as many persons as possible before killing himself. It's a very American slang as it's often happened in the hellhole south of Canada.
Cinematic wide shot of an empty wooden park bench beside tram tracks in a large city park at golden hour, same art style, background and camera angle as the existing sheep image. A nervous, cartoonish purple sheep with big eyes and open mouth stands on the path near the tracks in front of the bench. ...