"tragic accident" that would've resulted in a lot of lesser known people serving time, IMO.
There are people serving time. Hannah Gutierrez is (in charge of the guns). The Assistant Director, who handed AB the gun and told him it was safe, also took a plea.
I did some more reading on this and the judge had ruled that his role as a producer wasn't relevant to this trial. There were 13 different producers and apparently his role as producer was limited to the ability to change lines and maybe something else creatively. His role didn't involve hiring the crew like the armorer so it's unclear how much he knew about her experience.