Li Lanxi is an experienced actress, a recipient of Best Actress awards. She has played the role of green tea bitches before, so she guessed a little about what was going on in Zhang Ziyue's mind.
She has wanted to teach this woman a lesson for a long time. Now, witnessing Zhang Ziyue's reaction enabled her to find a tactic to drive Zhang Ziyue mad enough to spit blood.
Zhang Ziyue was still holding on mainly because Li Lanxi was Mu Lingqian's fiancée. She had learned about Li Lanxi being Mu Lingqian's fiancée from the news. Her brother warned her only about offending Mu Lingqian without specifying how she had done so.
She was unaware of the relationship between Wen Xiangyang and Mu Lingqian. She naturally assumed that she had offended Li Lanxi. She couldn't afford to offend Li Lanxi, so she could only endure it.
But, she was almost vomiting blood from suppressing her anger.