Being the only student made it difficult for her to ask questions. Moreover, in such a surgical setting, medical students are expected to observe first and then discuss with the teachers afterward. If there were more students, she could exchange a few words with her classmates. Now, it's unlikely for her to exchange ideas with Xie Wanying.
Xie Wanying, being a surgical student, might not understand interventional surgery, and since she is a patient's family member, she probably isn't in the mood for academic discussions right now. Doctor Yang could only swallow her words.
