I think the rules for the Showdown Roll are worded in a confusing way. It looks like you add a d6 to the pool for each of the 3 questions you can answer, but it also says that each clue contributes a d6. It’s a little ambiguous as to whether you need to count up the clues or if you just need to have found at least 3 clues
This is also a problem I have with the rules for External Containment Bureau. I like the mystery solving from The Between and Apocalypse Keys, but the Move is only about counting the clues that are part of your theory. When I first read ECB, I thought that you made a separate Theory Roll for each question you try to answer and whether you had found every clue.