After hearing Kieran reject Tanya, other than Jen who was confused all the time, the inspector and Kana were also puzzled by his actions.
From their perspective, it was a good way to get more leads.
"I don't trust divinations," Kieran said.
It wasn't wholly the truth but it wasn't entirely false either.
He was quite reserved towards divination, prophecies and such, especially the one from Tanya.
It was not because of her heavy eighth-grade syndrome but the entire situation.
All the coincident occurrences were pointing at a mastermind, controlling the situation behind the scenes.
He couldn't be sure who the person was right now, nor the goal of the mastermind but he was sure about one thing. Based on the understanding of the mastermind of Saint Brilliant, he must have done his research on Tanya as well.
Or in other words, it was because of the mastermind's intensive understanding of the school, his scheming would work.
