The solution to where I was stuck, I saw, could be pretty much the same as the situation that got me going—an explosion instead of a plague, but still one quick, hard slash of the Gordian knot.
The Gordian Knot is a legend of Phrygian Gordium associated with Alexander the Great. It is often used as a metaphor for an intractable problem (disentangling an "impossible" knot) solved easily by loophole or "thinking outside the box" ("cutting the Gordian knot"):