CHICAGO (CBS) – You can never predict a tragedy like the school shooting massacre in Newtown, Conn., but schools prepare as much as they can. Just this week, a school in north suburban Zion held a drill for a shooting.

CBS 2′s Suzanne Le Mignot reports on what officials learned.

“Whenever you have a lockdown, you get in like a corner, like a side of a wall, and you lay there and don’t talk … so they know you’re not there,” Zion Central Middle School student Jonathan Phillips said.

Jonathan, 12, took part in the school’s lockdown drill on Tuesday.

Principal Joseph Kent said, “Obviously, you never know when something is going to happen. What you do hope if that something happens, that all of your teachers are on board, that everyone knows what to do, from the students, at that time, that can save their lives.”

Kent said there are three lockdown drills held at his middle school each year.

“The teachers, at that time, then begin to lock their doors. Students are getting out of the hallways,” he said. “We heavily involve our police department, and we have a K-9 unit come in as well.”

Zion Police Chief Wayne Brooks said the police response during such drills is known as “rapid deployment response.”

“Meaning, in the worst case scenario, there’s an active shooter and what we’re trained to do now – actually post-Columbine – is to immediately enter the school, find the threat and control that,” Brooks said.

Student Keisha McClelland said, “Knowing that they do it, I feel more safe in the school.”

The Chicago Public Schools’ safety and security office said Friday that they have reminded all principals to ensure their schools are prepared.

“All Chicago Public Schools have well-developed plans in place to prevent this type of situation as well as plans for a coordinated response in the event of an incident,” CPS officials wrote in a memo sent to principals on Friday.

Principals were urged to review their school’s emergency management and school safety plans, review the drill procedures with their staff. They were also told to conduct their annual emergency drills immediately if not done so already.

CPS also told principals to remind staff that all exterior doors at their schools should be secured at all times, all students and staff should wear any required ID cards at all times, and all visitors must go through required entry processes and sign-in procedures.

School staff were reminded to approach or question anyone not displaying appropriate ID inside a school to make sure they belong in the building. Security officers were also reminded to make perimeter searches and “walk down” procedures throughout the school day to monitor for possible threats.