He knew that she was breaking through a door with the intention of attacking members of Congress. He knew that there were bombs placed at the DNC. He knew that the rioters are shown guns. And most of all, he knew that she was refusing to stop trying to get past the door.It's irrelevant. If it was in her pocket, unless Byrd was psychic or something, a hidden pocketknife is not a weapon threat as it no accessed, not brandished or otherwise visible, and folded closed and Byrd didn't know it was there. It is irrelevant.
Byrd had no knowledge she had it, and even if he did know, because it was in her pocket and folded shut, it wasn't an immediate threat. That means he had no justification on that basis for use of lethal force under his use of force guidelines.