No...I watched that part twice specifically cause I wanted to see if Lori reacted that way to Rick telling her something about Shane or about Carl. As soon as he told her about Carl shooting walker Shane, THAT'S when she pulled away and freaked out.
From a recap site:
http://betterwithpopcorn.com/blog/pa...ide-dying-fire
"The group, especially Glenn, argues with Rick on how he could keep such a secret from them. Unable to tolerate their bickering, Rick storms off alone, but is soon accompanied by Lori. Rick proceeds to tell Lori how he killed Shane. He tells her that he had no choice, but deep inside he wanted him dead. Lori looks shattered, and then Rick tells her how Carl put down Shane's reanimated corpse, which leaves her devastated. Rick tries to comfort her, but she wants no part of him."
When Lori first hears of Shane's death, she's upset...I mean, she was still close to him, but she was at least calm. Her finding out Carl shot Shane is when she lost it and wouldn't allow Rick to console/touch her.
I still think that Lori is ultimately OK with Rick killing Shane. Even if she wanted Shane gone, it's still going to affect her when she learns it actually happened. Lori's issue was Carl being the one to kill a zombie, and not only a zombie, but Shane as a zombie. Carl's never killed anything and up until then was her little boy. Now he's been pulled in to all the craziness, 100%.