I hope it turns out well for everyone and that your school does a better job at lockdown than ours. Maybe the staff will keep them entertained so they are not thinking about it.
Both my kids were in lockdown a 3 years ago when they were in 2nd and 4th grade. They were out waiting for the school bus, all the buses had left already except for the one my kids take. They had just gotten on the bus when someone spotted some boisterous teens from the neighboring alternative High School walking toward the playground with what appeared to be a gun. The principal had the kids walk from the bus to a classroom in which the entire long wall was made of windows that faced the playground. Why he thought this was a good idea is beyond me - why not an interior classroom with windows to the courtyard, or the gym or a windowless room? All the remaining students and a few staff were in the room, duck-and-cover earthquake style under the desks. I think there were only about a dozen students. The principal and office staff were in the office. NO ONE BOTHERED TO CALL THE PARENTS!!! I was wondering why the bus was so late and was calling the district office who knew NOTHING. No one was keeping a close eye on the kids in the classroom, because my way too curious DS got up and walked to the windows and watched all unfold. She said she saw the teens run onto the playground with their gun, and a whole bunch of men in vests sneaking running and hiding around the school grounds with their guns out and pointed toward the teens.
The bus finally brought my kids home an hour late with NO EXPLANATION! I had to do an internet search of the local newspaper that evening to verify what my kids were telling me. Later in the evening I got some short call, I think it may have even been recorded and it was the same call that went out to all the parents of kids who attend the school. Nothing specific to the parents of the few kids who were there at the time. There was no mention of men with guns drawn or anything. The ink to the newspaper article is below. I was volunteering at the school the next day and I told my daughter's 2nd grade teacher what Olivia said she saw. I was told she was lying, that no kids ever saw the gun, and Olivia never went to the window because they kept all the kids safely hidden. Later in the day, the teacher went into the teachers lounge and repeated what I told her Olivia saw. She came back and said Olivia's observation was true. A SWAT team had been called out, some of the police were plain-clothes, and they pretty much surrounded the schools. She was sent to the school counselor and told not to repeat what she saw to anyone as it might scare the kids! I was furious! I wated to know why the parents were not called. I was told the principal and office staff could not access the list of kids who ride that bus, nor could they get to a phone from where they were hiding (yet they thought it was fine to put the kids in the room with a wall of windows facing the playground!).
The blinds they mention in the newspaper article below are in the office. I don't recall seeing any blinds in the classroom. Certainly they were not down if Olivia watched it all unfold.
http://snovalleystar.com/2009/01/28/fake-gun-scare-causes-school-lockdown