"Lockdown, lockdown, lockdown. This is a drill."
With those seven words, calmly announced over the intercom system, an eerie silence overtook a bustling elementary school of 650 students in suburban Indianapolis. Lights were turned off and blinds shut. In some classrooms, doors were barricaded with small desks and chairs.
From start to finish, the "intruder drill" at the Forest Dale Elementary School in Carmel took about 10 minutes — an exercise now as routine at the school as a fire drill. What might sound terrifying to some parents has become the norm in many schools nationwide after a rash of school shootings.
More than two-thirds of school districts surveyed by the U.S. Government Accountability Office conduct "active shooter" exercises.
Some schools make their drills very realistic, simulating the sounds of gunshots and using smoke and fake blood. In one case, armed police officers with weapons drawn burst into a Florida middle school, terrifying staff and students alike.
Staff and teachers are usually given warning that drills will happen.
GAO investigators said one district noted "the difficulty of striking a balance between providing knowledge and inciting fear, particularly at schools with younger children."
Between 2000 and 2013, there were 25 shootings at U.S. elementary and secondary schools, resulting in 57 deaths, according to the FBI.
These numbers include the shooting at Connecticut's Sandy Hook Elementary School in 2012 when an intruder gunned down 20 first-graders and six educators.
Students at Forest Dale began participating in twice-a-semester intruder drills even before Sandy Hook.
"We do fire drills, but we don't expect there to be a fire. When you get on an airplane, they talk to you about all sorts of safety procedures, but not because they expect the plane to crash, but because you just need to know, just in case," said D.J. Schoeff, a school resource officer in Carmel and a regional director with the National Association of School Resource Officers.
But Forest Dale's drills don't have the effects and props that have drawn criticism elsewhere.
Playing the role of intruders, Forest Dale Principal Deanna Pitman and Police Officer Greg Dewald walked the halls, jiggled the doorknobs of darkened classrooms, checking for unlocked doors. A staff assistant in an office watching a monitor used the intercom to broadcast the location and description of the intruders, so staff and students could choose how to respond.
"Mrs. Pitman is wearing a green blouse today and Officer Dewald is wearing khaki pants with his policeman's jacket," the assistant said. "Consider what you would do if they were in the fifth-grade pod."
Fifth-graders scattered from a hallway, leaving notebooks and pencils strewn across the carpeted floor as they fled inside a classroom. At the other end of the school, youngsters streamed outside in lines of two with their teachers to designated safe locations.
Students had no advance warning of the drill. Teachers were told there would be a drill, but they didn't know what kind or when.
Inside the school, all went mostly according to plan. No children were stranded in hallways. Doors were locked. Only the head of one little child could be seen peeking out from under a desk. The child quickly popped back under the desk as Pitman walked by a classroom window.
Outside school, one class went to the wrong safe spot — a "lessons learned" moment for future drills, Pitman said.
"We had a little bit of concern from parents when we first started the drills," Pitman said after the students were back to class. "I think it was more of the unknown, and not necessarily anxiety over lockdown and intruder drills. Once they know what the teachers are saying to the kids, we don't really get a lot of pushback."
Not all schools feel the same way about the drills, and some security experts are cautious about them.
"Practice your lockdowns and diversify when you do those, different times of the day, and keep your focus on the other types of threats and day-to-day security issues without getting a tunnel vision focus on active shooters," said school safety consultant Ken Trump.
Many schools across the country don't have enough security cameras to capture the entire campus for potential threats, Trump added.
He said exiting the building can be risky if there truly is an intruder because of the uncertainty about whether there could be accomplices outside waiting. "You are leaving secure areas and evacuating into — you don't know what," said Trump, president of National School Safety and Security Services in Cleveland.
But a school psychologist, Dr. Melissa Reeves, says schools need to be prepared and conduct age-appropriate exercises like the Forest Dale drill. It's the more realistic simulation drills with props that worry Reeves.
"We do not light a fire in the hallway to practice fire drills, so why do we feel the need to bring in a fake gun, people screaming and people with makeup that looks like blood?," said Reeves, a psychologist at a pre-K through 12 school in Charlotte, North Carolina, and the president-elect of the National Association of School Psychologists. "There are other ways we can train staff members and students to be prepared."
Jennifer Cassidy, who has a second-grader and fifth-grader at Forest Dale, says her kids never come home talking about the intruder drills.
"I don't think that's because they are traumatized or freaked out. I think they just think it's just another part of school," she said. "At first I felt like, I don't understand why we have to do these. Then, after Sandy Hook, I was glad we do these, and I feel completely different about them."