It’s complex, the key phrase is “about to inflict great bodily injury…”. Also, castle doctrine is not one specific law it is several laws that states use. In a castle doctrine state, you can shoot someone in your house regardless of whether you believe you’re in immediate danger. What you stated may be considered a piece of castle doctrine, but compared to other states it’s much more restrictive here. If you shoot a burglar on sight in Massachusetts, or beat him, and he was unarmed you are in potentially serious trouble if he is injured enough that he can’t walk away. It would be different in a state with true castle doctrine laws.