Zuko actually took a bite of food, but more out of thought than hunger. The pessimism was crushing, but he at least had obnoxiously strong willpower on his side-- it just barely kept him from throwing his hands in the air and demanding to know how they could possibly watch each others' backs against an all-powerful magic castle. ...Just barely.

Instead, he frowned down toward his food and focused on the other part of their conversation.

"This place acts like one big evil spirit. It never speaks, but it's obviously listening, and it keeps us and the town all trapped in its world. The Castle is at the center of it all-- the changes, the bubble of power, the ghosts --so, it's as if the Castle itself is the spirit."