Duncan had indeed sown a spark into the mirror image of the Frost City-State — but he felt it was far from enough.
He could distinctly sense that the situation in Frost was different from that in Prand. The spark he had thrown into "the other side of the mirror" did not spread rapidly, and his perception of the spark was greatly diminished and interfered with — he speculated that this might be due to a natural barrier between the "two sides of the mirror," or because the mirror image and the real world did not actually correspond accurately. The misaligned parts were interfering with his judgment.
Whatever the reason, he needed to find a way to strengthen the connection with the spark, and the connection with the White Oak and Agatha.
During the conversation, Vanna suddenly revealed a thoughtful expression, "Speaking of the mirror issue... Are you sure you saw the gatekeeper's figure in the reflection of the glass?"
"I can certainly be sure."
