Stone nodded, "Okay, then we'll decide on the Repeating Crossbow."
Assuming the map is more important than the Repeating Crossbow. Shana chose the Repeating Crossbow, sacrificing Nightmare's significant personal interest and damaging Shadow's interests, which has no benefits for Shana colluding with Nightmare. Assuming the Repeating Crossbow is more precious than the map, Shana seeks the greatest interest from the base's perspective.
Therefore, as long as Shana suggests choosing the Repeating Crossbow, she is considered a good person in Stone's eyes, confirming he didn't misjudge Shana. As for the matter between Shana and Nightmare, Stone believes that one shouldn't jump to conclusions lightly. Even if Shana is colluding with Nightmare, she hasn't done anything against the base so far.