I carry a regular hair comb. It is an unbreakable comb that I carry all the time. Although you cannot stab with the comb, it can be used very effectively to slash with to keep you or your fellow staff members safe during a life threatening assault.”
The same can be said for using a pen, a set of keys, a clipboard, or a chair as a defensive weapon. When caught in a position of dis-advantage, you need to do what you need to do to survive the encounter. Remember that all “justifiable” techniques aren’t trained.
Don’t forget that if someone is placing you in “danger of death or great bodily harm” and you would be justified in shooting them with a firearm but don’t happened to have one that there — other options may be considered, used, and justified.