Excitement lights up Diarmuid's face when she says she will help, but it fades when his ears catch the sound of the footsteps and the Avatar gives her warning. As much as he would like to stay and fight, she is more powerful than he is and so he listens to her. The book disappears into his bag and then he pulls his cloak of invisibility back around himself.

"Good luck!" His voice is barely more than a whisper as he dashes toward the back of the room with his bag and crawls behind some of the boxes. Sometimes being small comes in handy!