 The legal threshold for use of deadly force inside your home is much lower than on your porch or on your own lawn. Whenever possible, do not leave the safety of your home when hostile people are on your property. You are safer legally and physically inside your house. And finally, he was able to get his gun quickly while being chased by violent attackers. This tells me that he had the gun readily accessible either in a quick, open gun safe or on his person.