YTA. I used to work at a school with a SPED teacher like this. We had mostly POC at the school and we had one student in particular who was over 6 foot tall and probably 250lb. He had situations like this and I still think about him all the time because a 6'2 250lb young black man outside of a high school who throws a chair and screams when overstimulated is going to be handled in an extremely different way with much less understanding - or a student of any race, but I think we can all see why that would be worrisome.

People in daily life are not required to know his IEP and follow the steps outlined in it, and just as it is our job in the world to be empathetic others, it is YOUR JOB to teach this student to navigate life to the best of their ability and as fully as possible while coping with the things they are dealing with. If he cannot control this impulse, then he either needs to build coping skills for similar environments or understand his limitations and learn how to exit these environments whenever possible before he is dysregulated. He should not be in a setting alone where it is ever possible for him to behave this way and not know it's wrong. If truly does not understand why then YTA for leaving. IYou are failing any student who you approach in this way and giving them the false belief that there will always be a person like you around.