I imagine she may sue for emotional distress as she witnessed the shooting and was almost hit by the bullet herself. No idea how GA came to represent her though.
From an older article:
"My law firm, Allred, Maroko & Goldberg, and I represent Mamie Mitchell. Mamie was the Script Supervisor for the "
Rust" production," wrote Allred. "She was standing very close to Halyna Hutchins and the director, Joel Souza, when both Halyna and Joel were shot."
(...)
"We are conducting our own investigation of what happened because there are many unanswered questions," she said. "Mamie has been interviewed by the Sheriff’s Department. She has information and evidence which she believes will be helpful in this investigation."
(...)
The attorney concluded by explaining that Mitchell has been "traumatized" and will not be giving interviews to anyone outside of law enforcement...
Alec Baldwin's 'Rust' shooting being independently investigated by Gloria Allred: 'Many unanswered questions'