Just saying the "Oh he had body armor so he couldn't be stopped" line is a bit over stated.
Howdy Mobi!
Among the tools we use in the field, one of the first a new agent wants to get his hands upon, is the tactical bullet resistant vest.
The key word in that phrase.... resistant.
There ain't really any actual "bullet proof" vest.
The facts are not known what sort of vest he carried. Was it level 1? Level 2? Level 3? 3A? What?
Even if rated to stop bullets from SWAT rifles, incoming fire won't prevent damage, just bullet penetration.
But there are more factors to consider.
How old was the vest? There is a reason why LEO's will buy a new vest every 5 years. The stuff breaks down over time.
How effective does it remain after multiple round impacts?
All things considered, I'll wager that gas mask wasn't bullet resistant.
Anybody note that this person came from California? A state where similarly armored thugs fought off police after a bank robbery in a shoot-out wherein hundreds of rounds were fired at the bad guys and many police were injured? A spectacle that still draws viewers on television today.
Was the shooter's motive a perverse instant celebrity?
Body armor does not render the wearer invincible. Incoming rounds still can do damage, such as broken ribs and possible internal damage.
The only reason this jerk broke off his attack is because his AR-15 jammed. Otherwise, the number of injured or dead would have been much worse.
Blessings,
M-Taliesin