Instead of following Mei Nan's advice and choose one of the three master builders as his teacher, he talked to everyone first. After having a short chat, he was confident that Messenger, the weakest master builder, would the best among the three when it came to teaching.
Although she was timid and reluctant to speak, not to mention she kept covering her face with her hood, she demonstrated the quintessence of LEGO in great detail. Besides, she remained patient even after Zhang Heng asked her multiple questions. In a way, she was very similar to the man in shorts that Zhang Heng met in the deserted island quest.