I know, that's why I added "hmmm".
However negligent behavior that causes something like this is still accidental, in the sense that it's not deliberate, just negligent. Which of course is the term I should have used, Negligent Discharge.
A negligent discharge is caused by either ignorance or carelessness.The person can be considered ignorant, if they have not been trained.
They are careless, if they disregard their training.