2 things that have crossed my mind about this.
It seems like where they lost the fight was in their minds before it ever started, "They were PREPARING to go on duty". They would have had a better chance had they put on their "On Duty" mindset when they put on the Uniform. Dirt bags that see them in uniform don't know or care if they are "On Duty" yet, they see a Uniformed Cop . ( I hope I expressed that clearly)
My second thought concerns the fact Clemmons WAS shot by one of the Officers. Some articles I've seen said in the stomach, others say in the chest. This underlines the need to keep pumping rounds into a threat until it goes down.
While I disagree with Rob that the Mozambique drill is not good for TRAINING, you MUST avoid the mindset of firing 2 or three rounds and "assessing". If the threat is still upright and facing you there is nothing to assess, keep hammering it, compared to your life ammo is cheap.