It’s Latin for “a person not welcome”

At the end of the article, which is already a litany of clownish buffoonery, it states that after destroying (effectively) the MRI machine in order to retrieve the rifle, he failed to retrieve a loaded magazine. So it was just left on the floor as they left.

Edit: autocorrect had changed it to clownfish

Or perhaps JSters (pronounced Jesters)*

*Meant as a turn of phrase and not a criticism of the language.