The more relevant rodef in this case is Chauvin
Had a bystander killed Chauvin DURING his act of murder, while Chauvin was murdering his restrained, harmless (unconscious!) victim.
Chauvin’s killer would be fully justified, and no less a hero than Nicholas Reardon who saved another victim.
Note: Although at the time Chauvin was a rodef, he is no longer one, killing him today would not be justified, don’t make the same mistake the OP made .