Everybody has a plan until the shooting starts. Things break down pretty fast. Odd are, this is the first firefight the officers have ever been in. I can’t blame them for not doing everything by the book in their first actual combat.
I can blame them. They are supposed to be professionals. They are paid to be professional. No one is perfect but these are grievous errors.
Most departments are pretty lax about these things. I read of numerous “accidental discharges,” in many departments. Seldom is anything done. Amongst professionals, there is no such thing as an accidental discharge. There are only negligent discharges. As in the Marine Corps, when such things happen, the perpetrator of negligence needs to be disciplined. I’ve never known of anyone in the Corps who had a negligent discharge who didn’t lose rank.