Having served on a School Board, I can tell you that school district personnel tend to ‘circle the wagons’ and are protective of staff members when major incidents arise. They act like its a big “family” and you don’t hurt family members. If a principal, a teacher or a custodian left a door unlocked and open, the School Board may be forced to treat this as a “non-public” HR matter and keep things quiet if they can. Most public education employees are in one labor union or another - including admistrators like building Principals. The School Board and Superintendent’s office get hamstrung by “confidentiality rules” imposed by union CBAs when disputes or misconduct arise. Just one more negative of protectionist education unions.
This is also why any CCTV videos of that day’s tragedy may never get released. The public sector protects its own.
yes, you are correct. In a situation like this they will need to find out how the door was left open, it was a single point of failure.