The "prosecution's case" is 2nd degree murder.
How does "profiling him" prove "evincing a depraved mind showing no regard for human life"? THAT is the legal standard to prove 2nd degree murder in FL.
Remember, FL law (776.041) allows any "initial aggressor" (if it can even be proved beyond a reasonable doubt that GZ was the initial aggressor) to regain their right of justifiable homicide/self defense after they withdraw from the initial contact.
GZ's statement (and there is nothing offered so far to refute it) is that he was walking back to his vehicle when he was attacked, therefore any actions he may have taken before that no longer matter - if he had a reasonable belief he was in peril of loss of life or great bodily harm, the homicide is justified, and he walks.