Yup, they did. But, Williams escalated it. Whether it was warranted is a matter of opinion.
There's no sound, so we can't tell what was said. Williams said that he was afraid they would start shooting. I don't know what caused that concern, at the moment he acted, the perpetrator wasn't even pointing the gun at anyone. However, at the moment of his first shot, the perpetrator had just turned to look at Williams and was pointing the gun in his direction.
I’m guessing you would have kept everyone safe by not poking out your head?
I wouldn't have shot first with an innocent bystander near or behind the perp.
And, I wouldn't have shot first when there was a potentially armed accomplice, obstructed by two other innocent bystanders.
Williams didn't "escalate it". Williams brought to an end an attempted armed robbery. If you don't believe that Williams' actions were warranted, then you'll probably find yourself among a small minority who share your opinion.
Perhaps it was the ARMED ROBBERY!
Next time you feel like bitching about why we tolerate "political correctness," find a mirror!