I have seen a rabbit with no head that was shot by a .17hmr still "running" on youtube as have other members on here .
I shoot loads of rabbits in the brainbox with my .22lr and they still kick and kick and kick . it's the nervous system.
If you hit them in the brain and destroy the brain the nerves may still be active . That's the way it is .
i have chest shot rabbits and had them drop stone dead,no movement (.22lr)
Ted from Teds holdover has a video on it .
Google "disinhibition .headshot animals " and his video is there . ( I hope this is not classed as linking to dead stuff )