Diamonds are forever

It was really tempting to think that magic was infinite. Especially with artifacts like the amulet to aid her own potential.

But in the end it was just another form of energy and could be depleted... albeit temporarily. It needed to be periodically renewed, replenished. 

That was exactly what Queen Witch was banking on.

"Let's see how long you can go without rest, Director."

After all, keeping your subjects sleepless was a tried and true way of softening them up.

She didn't underestimate her opponent - while she herself took a nap, she had Swan put in a magically induced stasis.