Some teachers at a suburban Phoenix high school want to know why they weren’t forewarned of a fake gun drill that panicked dozens of students and wound up in a brief classroom lockdown. The school’s experience underscores the need for clear communication when planning such drills.

Four students brandishing fake guns stormed Hamilton High School in Chandler, Ariz., on May 21 as part of a law enforcement class drill, running through a hallway and screaming, “Don’t make me do it!”

One teacher frantically phoned the school’s front desk, which knew nothing about the drill that lasted less than 10 minutes.

Chandler police said school administrators approved the fake-gun drill, which is a routine part of most law-enforcement training classes, and Hamilton officials should have informed teachers and students.

“Had we known about the fake guns, we would have killed this exercise immediately,” said Hamilton’s assistant principal Dave Constance. “This is not an appropriate way to teach school safety.”

The school has offered counseling service to the dozens of students and handful of teachers who witnessed the drill.

“Those teachers and kids were in a panic because they thought this was real,” said Peggy Donahue, whose son attends Hamilton. “How could the school think it’s acceptable to have kids running through the hall with guns? You have fire drills without smoke. So can’t they teach safety without guns?”

About 25 Hamilton students and another 25 at Chandler High take the annual police- science classes taught by a city police officer.

Officials said the 23,000-student school district will now confine “realistic” drills of life-threatening scenarios to weekends or a police range.