Why does Michael Gartenschläger go to Büchen in the novel, The Wall Jumper?

Michael Gartenschläger goes to Büchen to steal a deadly self-activating robot detonator that has never been studied in the West. He succeed and sells his mechanical "comrade to a West German news magazine. Stealing a second one, he is arrested but undeterred. While stealing a third from specially-reinforced Büchen, he is riddled with bullets.