Assuming you and the BG are within reach, like the gun is almost touching your head, this is where some basic self defense classes would be helpful. Learning how to disarm people and proper ways to grab a gun or arm/wrist would buy you more time than trying to divert his/her attention long enough for you to draw and fire accurately. Sure, people can train and with practice get a draw and multiple shots on target in under a second, but thats at an accademy and not in a life or death sitution with the adrenaline rushing and your mind racing. Just a thought. I am going to look into some basic self defense classes like these for myself. You can never be too prepared!
SA XD .45 Compact -- 5" Colt XSE -- Glock 21SF
Savage Mark-II .22LR
Member:NRA, DU, PF
Ignorance can be fixed....its called education. Stupid will get you killed!