The protagonist feels trapped and wants to escape. When/how does Thomas show his desire to escape the Glade? In dialogue

Thomas wants all the Gladers to escape one day. For example Thomas reflects on Chuck's death, telling Teresa about the promise he made to him. Thomas's characterization as a savior of the Gladers and the resulting guilt he experiences when he is unable to save his friend, are foreshadowed throughout the novel. Chuck is set up as a character whose death will propel Thomas's development and motivation as a leader.

Thomas promises Chuck a stable life with a loving family, the type of fantasy any orphan might wish for themselves. It is essential for them to believe that such a life is possible, even if they may have their internal doubts. Thomas looks upon Chuck as a younger brother more than as a friend. He makes him this promise to help keep him calm and give him something to live for. Because Chuck willingly believes in Thomas, he is able to save Thomas's life by jumping in front of Gally's knife. This single final act by Chuck signals a potential for bravery and action that his character was never able to achieve during his short and tragic life. This fact only adds to Thomas's guilt over his friend's loss.

“I promised him!" he screamed, realizing even as he did so that his voice was laced with something wrong. Almost insanity. "I promised I'd save him, take him home! I promised him!”