OK, she was lucid when she realized she would have to kill each one separately in the basement. But maybe she experienced a fugue state each time she strangled them only to then realize when they were dead it was time to go get another child. This reminds me of the fugue state that Walter White planned out in Breaking bad. He exhibited great planning in devising a solid alibi for the two of them but then was in a total fugue state while executing the plan. Sure, he told the psychiatrist he made the whole thing up, but that is protected speech, that guy is not allowed to tell the cops.