Should I Resign Or Be Fired?

I'm employed as a substitute teacher in Texas and received a call from the school principal that I have been working as long time sub on Friday informing that I am no longer allowed on campus until next Friday due to being terminated. There was an incident where a child hurt himself and I was told after reviewing video said child was unsupervised for 3 minutes. There is about 4-5 adults who are to watch 80-90 small children on a playground. I was watching an area where said child was not at when the accident occurred. Principle said that I am being terminated due to "negligence". I have had issues with principle since the school year has started, she has always been very rude, belittling, and condescending towards me and a handful of other teachers. I say this because I have never had a nice or easy interaction with her until she called me to inform me about me being unable to return to the classroom and she sounded happy to inform me that I am being terminated.

If you have gotten this far, thank you. My question is if it best I resign via email to HR, return my keys and badge to the schools front office? or should I wait until Friday, when principal said to come , which is in 5 days to turn in my keys and badge? I will be on campus as a parent this week since my child is a student and I will be present for awards assembly. I have never been fired before and dont know how I should proceed. I dont want to be implicated in any wrong doing when I am not the only person supervising 80-90 children

Edit to add:

I told principal that I would be on campus for my Childs assembly and can leave my keys and badge at the time. She said I am more than welcome to be on campus as a parent and I said "of course I will be on campus as a parent." I am not trying or wanting to seek unemployment, have helped others with it and I honestly dont have the patience for the entire process.

it is me and another long term para who share a classroom, not the others who were outside at the time. Was told because the child is under our supervision when in school.

I'm not going to make a scene, I know what they are trying to prevent, I am just not that type of person. I speak very professionally and know how to maintain my composure in a professional setting, even when I dont agree with an individual.