I'm laying myself open to refutation- and that's fine. At my age I no longer mind being corrected. However, if my memory and/or experience is valid, there is a serious flaw in the design of elementary school rooms.

In the lower grades of school I don't remember a single schoolroom that had more than one door. That means that there is no way to escape if needed. There are windows, true, but windows by their nature are highly visible.

Hiding in coat closets is not only heart breaking but futile. I think every school in the country should cut a second door into every schoolroom. 99.99% of those second doors will never be needed but for those that are, it could mean the difference between multiple killings versus one or two.