This is not something that you can answer logically. You kinda react spontaneously in the heat of the moment so I don't know what I would do... I might chicken out or I might jump in like Rambo. It depends on my Google rankings that day.
No. I have kids, and they need a responsible adult in their lives. I do have a shitload of life insurance- so I'm not worried about the financial aspect, but they are definitely better off with me alive.
....some of these responses, lol. "If I was in love", fuck all that noise.. Women can be replaced, I however - cannot. So I'd bail like that dood did his kid. I got kids, a business, responsibilities. I'd starting using people as shields.
I would definitely put myself between any weapon and any family member I was with as I tried to diffuse the situation. So I might take a bullet while trying to stop him from shooting anyone but I don't know that the "flying in front of them", secret service style would happen.