Maybe it's supposed to make sense but it doesn't. Still, showing a weakness is a bad idea and Katniss decides to operate under the assumption that Finnick is right and she's not just insane. That's a possibility, isn't it? That the simplest solution is the correct one? She wishes that Beetee and Wiress were here to sort this out for her, or Haymitch. Haymitch is surprisingly clever when it comes to things like this.

"Let's say we did. I'm not any better off than you are knowing what the arena looks like. I still couldn't find Peeta or Beetee and I still don't know why Johanna tried to kill me." Katniss laughs awkwardly. "Other than, you know. The obvious reason. We had an alliance. Me, you, Mags and Peeta. Beetee and Wiress too, and Johanna got them for me. We were trying to kill the careers and get out."