I think what's being referred to is Russian roulette, which may not be in your mouth, and may not be because the bullets are old, but the core idea being that t

I think what's being referred to is Russian roulette, which may not be in your mouth, and may not be because the bullets are old, but the core idea being that there's some chance that the bad outcome happens (gum fires). Given the subject, quite ironic. Or not, since maybe it's less ironic and more exactly what were talking about.