Doctors recommended that Samanta Arjune not remove the bullet lodged in her left leg for fear that it would cause extensive damage.
The October 1, 2017, shooting in Las Vegas claimed the lives of 58 people, making it the deadliest shooting in United States history.
A lawyer for the victims hit back at the "outrageous" lawsuit.
Lawyers for police argued authorities could not release sealed documents because they are investigating more charges.
The three-day concert at the Mandalay Bay Resort and Casino included headliners Eric Church, Sam Hunt and Jason Aldean.