Another possibility is that the Quorum, paranoid and insecure bunch they have proven to be starts wondering if Lee or Bill is the final Cylon after all, and that one or both of them has led them there to go to their doom.
Also, Zarek may actually do what he does to try and give them a stable leader, somebody who can speak the voice of reason, knowing that if things are allowed to continue, disappointment will turn to panic, panic to anarchy, and anarchy will be the end of the human race. That could explain why he has the right motivation but no choice in the end.
D'anna speaking to the hybrid indicates that, yet again, the hybrids know more than they let on. Does the Final Cylon or God speak through them after all? Does D'anna think that the hybrid is the Final Cylon? That'd be a totally unexpected twist. We know it sees into the space between life and death, and that's where the Five seem to exist. So, it stands to reason it knows who the final Cylon is. Maybe D'anna will admit that she only saw 4 faces and lied about seeing the Fifth, so she goes to the hybrid to learn who the last one is. I've got this feeling that D'anna will meet her end when the Final Cylon is revealed - either it will kill her to protect its identity, or she will be killed accidentally, perhaps in the exchange of gunfire we're hearing about.