We ain’t dead.
I think she tests the battery looking for a sign. She wants to stay, but she’s so scared to. She thinks she doesn’t deserve to. She just killed Lizzie less than three days ago. 72 hours. So she pushes the button - if it’s dead she’ll stay, if it’s not - it’s a sign she shouldn’t be there.
She tests the battery, hoping for a sign, hoping for the choice to be out of her hands just this once.
Just this once.