It turns out that sleepwalking is inherited. Paige was sleepwalking and got out of the house in the middle of the night and took her parents car. Annalee realized what was happening and went looking for her. Paige was sleep-driving and hit and killed her mother.
Oh and Annalee's parasomnia manifested itself in having sex in her sleep. As long as Warren was home she had sleep-sex with him and had no need to go looking (sleepwalking) for anybody else.