What she doesn't have enough energy for is dealing with worrying - with fretting over time, or what the Demon Queen will do to her. She also doesn't have enough energy to keep watching the Demon Queen out of the corner of her eye like this, waiting for the other shoe to drop. (She doesn't know how to predict the woman.)

So, Lily retreats further into the false shelter of the aisles.

She will allow Lily to do so.

After the given amount of time has elapsed, she stands and goes over to Lily. "Up, child. Your training begins."

She stands with a sigh and a conflicted glance at her book. "Where do I put this?"

"Back on the shelf you got it from."

"Can I leave a bookmark in it?"

"You may."

She'd found one earlier, so she slips it into place and goes to put the book back where she found it. 

Then off to one of the training rooms, where the Demon Lord will recreate the situation where she first met Lily, and demonstrate each and every way she could have killed the girl, but didn't.

She fights back just as ferociously! (Though this time with something more like fear in her heart that escalates the longer the 'training' goes on - the repetition makes it worse and leaves her struggling to focus, to learn - her head unable to tell when and where she is - )

Learning is not exactly the goal at this moment, so.

She halts things in the early afternoon for a lunch break.

When the Demon Queen stops, Lily just sits there staring blankly into the distance. She doesn't make any effort to get up or eat.

Hmm. Suboptimal. Perhaps she's pushed too hard.

"Come, child. You've made it through the worst of today. Now eat. I will begin teaching you to properly wield that knife after."

She responds by curling in on herself a little. 

"By stabbing me with it?" she asks, so quietly she's nearly inaudible, though the bitterness in her tone is unmistakable.

"Not by stabbing you with it, no. We're going to try a different approach."

"All you've done."

"Not willing to take it on faith, hm? I suppose that's reasonable."

Extremely suspicious squint. 

"Perhaps you'd like to learn some magic, instead?"

She doesn't say anything, but her gaze is suddenly an interested kind of intent, rather than just eyeing the Demon Queen as if the woman is a venomous snake that's currently calm but was hissing and biting just a few minutes before. 

"I see I have your attention."

Noncommittal noise.

"It would be a theoretical discussion. No stabbing required. But I must insist you eat first."

...Depends on if she can get food without getting within arms reach or within half the room's length of the Demon Queen. If not, she's staying in her far corner. 

She'll send the tray sliding down the floor over to Lily.

She'll pick at her food a little, then. Eat the fruit, possibly some bread. Drink some water.