On some days, her mind slipped, and she would sit by the window looking for him.

But his mind had slipped where it wanted to go.

He seemed lost, as if his mind had slipped permanently into another age.

He noted it, and then his mind slipped back into its routine.

His mind slipped again, and when he awoke next it was dark.

She hoped his mind had not slipped over the edge.

She tried to think of all that could go wrong, but her mind just wouldn't slip into gear.

My mind sort of slips away and thinks about something else.

He tugged it free, but his mind was slipping away.

I've half a mind to slip something into her evening wine.