If such a thing happens, the argument would be the ROTC students, who just saw their officer teacher killed by this outbreak of Sudden Jihad Syndrome, killed the perp after rendering him unable to hurt anyone further.
Lethal force is allowed for stopping a threat, intentionally killing someone is reserved to the judiciary.
While the officer was a negro, if there's enough whites in the group you could see the new nigger AG who wants Republican children dead persecuting the students....