As you can tell from the final version, Grok completely switched which arm was holding her, and which was punching, and just had him grab her neck, rather than put her in a choke hold. I could have kept prompting to get it closer, but this was good enough.

Then I used the exact same prompt as above to create the first 10 seconds of the video.

For the first 10 second extension, I used this prompt:

He keeps punching, and blood begins shooting out of her mouth.

Then for the final 10 second extension, I used this prompt:

He winds up a HUGE hit that snaps her neck on impact, sending out a huge spout of blood, and swinging her body around and so that she lands on her back on that mat. The camera keeps her body and face center frame after she falls.

And you can see the final result above.