@georgetakei While distasteful and ill-advised in this context, it's an allusion to Gen. Mattis' dictum about situational awareness: "Be polite, be professional, but have a plan to kill everybody you meet."

It's a blunter, more individual version of Teddy Roosevelt's national defense recommendation: "speak softly, and carry a big stick." At least I /think/ that's the point the guest was trying to make.