(NEWSER) – A Chicago-area high school has an unconventional safety drill slated for today: During its "code red drill," Cary-Grove High School is going so far as to have someone in the hallway shoot blanks from a starter pistol. The point? "To provide our teachers and students some familiarity with the sound of gunfire," said the principal in a letter. Teachers will keep students inside, with doors locked and curtains drawn, as police sweep the school. Students are aware of the drill, and there will be a PA announcement beforehand, the Northwest Heraldreports.