The line comes from S.T.A.L.K.E.R. Shadow of Chernobyl, the 2007 first person shooter by GSC Game World set around the Chernobyl Exclusion Zone. A Duty guard posted at the entrance to the Bar area repeats the order to players who pause outside, with the fuller version continuing 'don't stand there.' Its blunt delivery made it one of the game's most quoted NPC barks, spreading through forums, videos and soundboards alongside other Zone phrases. It remains popular because the command works perfectly out of context.