Assassination

I'm watching a man aim a rifle into a crowd in an outdoor amphitheater from a grassy area at the read top. Others are walking by either not noticing or perceiving it as normal. Two other men carry parts of a complicated parabolic sound dish to where the man is standing and assemble them. The sound dish is actually a disguised rifle, the men fire it twice at their target, disassemble it and calmly walk away.