Her patience paid off, and her eyes widen slightly at the implication.

"Being able to hear them means it wasn't a one time spell... it wasn't like a geas," she thinks out loud. "So they were controlling him continually."

Willow looks at him earnestly, hand still on his, trying to prove her point that he was helpful. "See, I'd never have gotten that on my own, and that's a really important point."