Leoben: We'll rejoin your fleet within an hour. Roslin: Then we will return the final five to you. Biers: Four. There are four in your fleet. Roslin: Four? Where's the fifth? Biers: I want the four in your fleet.See how D'Anna avoids that question about where the fifth is? It's strongly implied she knows the answer, but doesn't want our heroes to know it. D'Anna is not omniscient, and she's been out of circulation for a while — so it's kind of odd that she knows the location of the fifth Cylon right off the bat like that.