Good for him, fortunately he is a retired LEO and can legally carry in Ca. certainly, preparation and practice played a role. if I were to travel there, I would have to either carry illegally or become a statistic.
I prefer to spend my vacation money in more hospitable locations but for the average joe finding himself in this situation;
I saw Massad Ayoob on personal defense Tivo awhile back and what he had to say related to a situation like this.
Whoever calls first gets to be the victim complainant {the only other role to play is that of the perpetrator}...The system is keyed on the assumption that whoever made the call is the victim.
5 Things to do after a shooting
1.Point out the perpetrator to the police, do not have your gun out if possible when they arrive, keep hands clearly visible.
2. You say "Officer this man attacked me, I will sign the complaint."
3. Point the evidence out to the police.
Example: 9mm casings are the perfect size to wedge into shoe treads and car treads to be carried off the scene. Wind on Icy surfaces will blow them far away, etc.. If your defense hinges on you saying "he shot first" you will want the cops to be aware of his spent casings to support your claim.
4. Point out the witnesses {before the police arrive get them to hang around.}
5.Tell the police "I will give you my full co-operation in 24 hours after I have had a chance to consult with my attorney". If a cop plays the game of "come on, we are on your side." {or someting like that} politely tell them that when an officer is involved in a shooting, the same courtesy is understood.
After that..Name, rank, and serial number is all they get until you talk to your lawyer. After that, you discuss nothing without your lawyer present.
And these videos are well worth 45 minutes of your time;
"Don't Talk to the Police" by Professor James Duane
"Don't Talk to the Police" by Officer George Bruch