Mary in Heaven...I think you're onto something
Strip the flesh, salt the wound!
What will be written on my tombstone when I die? "I just saw him yesterday"
1st responders would have taken the brunt of inital deaths since they would be on scene before most anyone else. LAPD is sensitive to the idea of riots due to a history with them. The initial police units deployed would have been over run. The sop for riots is to encircle it and let it burn out like a wildfire with riot officers being the fireline using non lethal weapons as well as tear gas. As we noted this wouldn't do well at all against undead so behind them would be officers armed with live ammunition. This is where your SWAT teams would be along with officers called in for duty. It would be city wide and I agree with what was said before about police trained to shoot ceneter mass and not head shots. Couple this into seeing the undead for the first time with them attacking and using your buddies as nom noms could easily have the police outnumbered and overrun early in the game. Include EMT's and fire department personal taking wounded to hospitals and we see where these responders disappeared to as well. This could easily all take place within 30 minutes to an hour. Also typically National Guard is called out before regular military and reserves since the Governor can issue there call up without federal authority from D.C. So for Micheal, Saul, and Angel's unit to be called up so quickly would mean the shit really had hit the fan. We may see other first responders further out from the epicenters of the outbreak if they were able to get word as to how to survive before it reacehed them.
Death's Clock Never Stops Ticking!
The cops are all dead or zombies at this point. maybe they will learn how to shoot.
They're first responders, so they would have been hit the hardest first when the outbreak started