" Besides,” she said, “there was always a chance I might escape.”
He snorted. “And dragons might start eating grass.”
“Even so, I had to try.”
“I understand. If I could have, I would have done the same when the Twins first brought me here.”
“And now?”
“I still can’t, and even if I could, what purpose would it serve?”
To that, she had no answer. Silence followed, and then she said, “Murtagh, if it’s not possible to free me from here, then I want your promise that you’ll help me escape by…other means. I wouldn’t ask…I wouldn’t place this burden upon you, but your assistance would make the task easier, and I may not have the opportunity to do it myself.” His lips grew thin and hard as she spoke, but he did not interrupt. “Whatever happens, I won’t allow myself to become a plaything for Galbatorix to order about as he will. I’ll do anything, anything at all to avoid that fate. Can you understand that?”
His chin dipped in a short nod.
“Then do I have your word?”
He looked down and clenched his fists, his breathing ragged. “You do. "

― Christopher Paolini , Inheritance (The Inheritance Cycle, #4)