Threatening music plays as the American heroine approaches the border between El Paso, Texas, and Ciudad Juarez, Mexico, in the movie trailer. Crossing the line, a fierce firefight breaks out. “Nothing will make sense to your American ears,” says a mysterious voice. Flashes of more blood and explosions follow, before fixing on the ominous word, Sicario, the Latin American term for drug cartel hit man and name of the action thriller that debuted Thursday with stars Josh Brolin, Emily Blunt and Benicio del Toro. On a real border crossing from El Paso to Juarez on Sunday, motorists saw a rather different sight.