The officer would have been trained to control the situation. Rushing in to tackle that woman and ending up in a wrestling match with her having a knife means he lost control of the situation. What if someone else decides to jump in on her side? There's lots of other people there. His best course of action is stop her action by shooting her and maintaining control over the whole group of people there at a distance.
When the fat bitch says she's "Gonna kill you" to 'pinky' that and the obvious knife are more than enough for him to shoot her to stop the action. He did the right thing.
I never said "tackle the woman".
BTW sorry for the delay in response. The internet was down for some reason. Now it's back on. Then I did a speed test. HOLY SHIT it went up to 250 megabits per second.
They must have just did an update in this city.