The jury has previously been played body-cam footage of the moments after the incident.

Why only after.

The incident involved two knives. Here's a picture of them (from the linked article):

The officer tased a 95-year old woman, who needed a walker to move about, because she was holding a steak knife.
Ya, I get not wanted to get a bit of a ragged cut, but Jesus Zombie Christ, that situation sounds less threatening than a box full of kittens.