It’s not real obvious where her feelings towards him are coming from. They’ve only spent two or three hours together, most of which was spent quibbling over whether torture was justified or not.
Love at first sight, I guess.
Personal guess is that the tank he breathed in was half of the mix, and you’d need to be exposed to the other half to get a lethal reaction.
Going against everything she’s been taught makes him a Bad Boy. She wants to sit on his shoulders at an Elvis concert.
My personal guess is that G-d doesn’t want to piss Jack off. 
What I found astounding is given the history from the last 6 seasons in the “24-verse”, people still continue to run for president there. It’s not an office with a high life expectancy. Get elected president in the 24-verse, and you and/or your family will not survive your 4-year term…
What the hell, the Kennedy family did it. The Romanovs, for that matter, and for a lot longer.
If Jack Bauer had gone on the mission, he would have tortured the real location of the bioweapons out of Seaton before the last commercial break…