I changed the start of the story. I did some research about PTSD. There are lots of “triggers” can cause people who had PTSD re-experiencing of traumatic events like nightmares, flashbacks and painful thoughts. The reason why I put the character on the street is I want to express this kind of negative feeling will happen without warning. One second before she walking on the street just like the other people but suddenly everything change and become aggressive. But she could do nothing because the feeling is so strong.
And the part that she is enjoying the music. I keep the music bar behind her. Her expression will be more and more relaxed with music. It may show how music treats her mind.