Then according to a woman they interviewed, she (and maybe he) was/were made to leave the performance venue. There may be nothing to it but the witness sounded sincere and wasn't present when the shooting started.
While it’s a possibility, you’d think if she were there to warn people she would have told it to the security people who dragged her off.
Security had already removed her.......Likely just a nut job because if she had prior knowledge she would have gone to the police