Maybe instead of hitting or throwing, she does claw at people in an attempt to get people's attention. If she had problems coping with anxiety, and there's no quiet room available, she does retreat to the corner and start rocking and moaning, sometimes screaming.
Clawing and regressive behavior like rocking and moaning strikes me as more autistic than anything else.
When I have anxiety attacks, I'm more likely to hit or throw, but my larger underlying compulsion which I'm resisting is to bang my head against the wall. As a child, I would have seen being sent to a quiet room as a punishment and felt like it was unfair because it was somebody else who did this to me. No, it's not logical or reasonable, but that's how it worked for me.
True story: one time I had an episode like this and a teacher sent me into the hallway. I was carrying an umbrella and I decided to swing it at a bank of lockers. Little did I know that the teacher had followed me out and I almost caught him in the head. He tried to have me expelled.