From the prolific author, Greg Perry (about eBay and sundry computer topics:
My bride, a former public school ... just told me this: Lockdown is nothing more than an attempt to keep collateral damage to a fixed number. Its their (failed) hope that the maximum number of students who will die will be the number locked inside the room or hall with the shooter.
from the Freemendo at Typepad blog 04 November 2007 Lockdown
Lockdown, lockdown, lockdown. No, no, no. When the terrorists began their assault at Beslan, around 40% of the students and staff ran like cuh-razy to get away from the school. A few hid in the boiler room. Every single one of those children and adults lived.