After all, Haiyuan Ai, like Conan, came down after taking the medicine of the dark group.
Mourning is because my sister Miyano Akemi didn't want to stay in the dark organization after she was assassinated by the dark organization, so she took the medicine APTX4869 and was saved by Dr. Ali.
In the episode where she first appeared, she said that because she is in the same situation as Kudou Shinichi, I believe Kudo can understand her.
After so long, Conan spent so much time with Ai. I think it should be a feeling of sharing weal and woe.