there is no rest at the portal
Being a demon in possession of a healthy human body means that you don't have to sleep.
This suits Ruby just fine. Time out of it is time wasted, and there's too much to do. Sure, the physical part of sleeping is good (almost as good as ice-cream, or chocolate, or the first sniff of a cup of good coffee, or a perfect sunset, or plenty of garlic and red wine in the spaghetti, or . . .), but it's not strictly necessary. All you have to do is let the body rest. Maybe shut the eyes a bit. Maybe let the hands lie still. The mind can keep on working.
And then there's the part that she wonders if other demons have too, but that none of them talk about; the part of sleep called dreams, and the part of dreams that has her waking and listening to the voices tell her that the escape itself was the dream, but now she's back in Hell, and she won't be leaving again.
And then she wakes up.
Or maybe she's dreaming again.
Maybe some more coffee can help. She can always rest the body tomorrow.