but this does highlight the ambiguous nature of this SYG law.
It is poorly conceived because it makes deciding what is and isn't self defense pretty difficult and potentially encourages people using force when they do not need to.
With GZ / TM it's actually hard to come up with a much better example of legitimate self-defense - you are on the ground being pummelled by a sustained attack. It's really a no brainer - it's clearly self-defense.
Change the scenario to merely being threatened and having the means to escape but chosing not to ... much harder to decipher what is happening and what reasonable force is and where the fault lies. What if TM had merely threatened GZ and GZ was at his car and could just get in and drive off but decides instead he can "stand his ground" ...
The Alexander case was obviously neither though as she chose to return with a drawn gun - that changes everything and makes her an aggressor and firing it makes it a 20 year sentence.