Any further use of the weapon, however, would depend on the justifiability of the situation, requiring being in jeopardy of lethal harm. There is nothing that I know of (at least in Oregon) that legally demands someone be forced behind the curve (denied the right to draw as warning) and hamstrung up until the point of actual lethal force being executed against a person (which, almost by definition, would be too late). The moment someone reasonably believes a deadly attack is about to occur, one may actually use the gun (fire) in defense. (ORS 161.209, ORS 161.219) The reality is, the mere fact the BG attempts to surmount the initial drawing and defensive posture makes a strong case that the BG believes he can overcome the defense and commit his violent attack.
test case material? Possibly. But if my life and that of my child is being put at risk by someone growing more violent by the moment, and that person decides to rush me in attempt to disarm me after being clearly warned of the result of any continuation of the flow of his violence, I would not allow him to make it to my child. Either the car, my firearm or some other method is going to stop the BG short of that goal, if I'm able. Nothing in law (so far as I am able to find) demands I succumb to a violent attack in that manner, nor allow my child to endure such an attack. The BG would be stopped, lethally if he required it.
Note: As always, none of these comments are intended to be construed as legal advice or recommendations. These are simply made as my interpretation of the relevant statutes and a description of the manner of my (planned) self-defense in such a hypothetical scenario.