Elizabeth Mitchell Interviews with Spoilers

   We’ll also get some clarity on Charlie’s mom, Rachel, played by Lost vet Elizabeth Mitchell, who isn’t as dead as her family thinks. "I asked [Kripke] if my character is some sort of sociopath, because I couldn’t see any other way a woman would leave her children like that — especially in a national crisis," says Mitchell. "But I keep getting told she’s a good person, really strong and a true survivor. You’ll just have to cut her some slack."
Source: TVGuide

   Question: I’m glad to see Revolution doing well, but where did Elizabeth Mitchell vanish to so soon? She’s one of the main reasons I’m watching. –Jerry Ausiello: Don’t worry, she didn’t get Lost — Rachel is seen again in Episode 5 (airing Oct. 15), in which Mitchell says “we learn quite a bit” about “the ins and outs of her leaving” her family. But it’s in Episode 7, she says, that “we find out 100 percent for sure” how it is that she wound up in Monroe’s possession.
Source: TVLine

Thanks to Elizabeth-Mitchell.org