What does Miss Pross, to the end of her life, remember about Sydney’s face and arm as he escorted her back to the Darnay house? (From Book 2 Chapters 6-10)

From the text:

Miss Pross recalled soon afterwards, and to the end of her life remembered, that as she pressed her hands on Sydney's arm and looked up in his face, imploring him to do no hurt to Solomon, there was a braced purpose in the arm and a kind of inspiration in the eyes, which not only contradicted his light manner, but changed and raised the man. She was too much occupied then with fears for the brother who so little deserved her affection, and with Sydney's friendly reassurances, adequately to heed what she observed.