Regarding Tori...
It helped for me to think of her as "triggering." It was clearly more subtle and pervasive than Boomer's trigger to shoot Adama, but it seemed to me that this may have been an example of what happens when one of the Finals (who are in much deeper 'cover' than the infiltrators of the Seven) hits a programmed response. Their ordinary personality takes a hike.
Alternative theory:
To Tori, this was a "it's her or me," situation. Cally could be calmed down for the moment, but sooner or later she WOULD crack. She'd tell. She -knew the secret-. There was only one way out. Tori has a soft exterior, but I think she's hard inside. When it comes to her life or your life...she will kill you.
-- Final analysis.
The idea there was programming involved is supported by the fact that she took great pains to save the baby. The Tori of the alternative theory might not have cared...and even if she did, she'd be unlikely to risk much to save Hera anyway. That she went in to confront Cally...who'd just beat the -crap- out of her husband...and save the baby says to me that she was under certain imperatives that might not have been entirely her own.
Oh! And about Roslin!
I find Roslin's "journey" in the show to be really interesting, and kind of tragic. She started out this beleaguered, inexperienced teacher, in way over her head, trying desperately not to screw things up...and finding she could do it after all. She was excited, intimidated, and ultimately (I think) deeply honored to feel that she had a place in the prophecies. But she let that sense of honor turn into pride...she was the chosen one! That was only inflamed by the realization that she was dying...and had a very limited timetable to fulfill her destiny. The Baltar Fiasco too had destructive effects on her, making her cynical and untrusting of democracy (they elected Baltar after all).
This has all combined to mold her into the person she is now. In her mind, she is the hero of humanity...destined to lead them to a new world. She is RIGHT. No one else is. Democracy is irrelevant; there will be time for luxuries like that on Earth. Right now she has to save everyone! Nothing can stand in the way of that! Not even good intentions.
We can see her more clearly. Having bought into her own mythos, Roslin now strikes out at anything and anyone that threatens it. Noteably Starbuck...I think Roslin had good reasons to distrust her...but the REAL reason was because Starbuck has always been a "child of destiny" too. The Arrow. The whorly pattern. She's in it deep, and now seems to be set to steal away Roslin's title of saviour. Of COURSE Roz hates her. Lee is similarly undermining Roz's other claim to power; the political process. She has so far lashed out at both.
I can't find it in my heart to hate her...though I would certainly not want her in charge anymore. Destiny has not been kind to Roslin, and she has fought long and hard to protect humankind from monsters...only to become one herself.