This thread is pretty well full but I'll pile on with yet another vote to NEVER leave a firearm in an unattended vehicle.
I've always been of the mind set that I wouldn't think of leaving a baby in a vehicle unattended because someone could steal it, or else, being locked up in a vehicle could kill it.
Someone most likely will eventually steal your gun if left in the car. And how about the elements outside? Humidity, heat, cold, all cycled constantly. Given time, your gun will show the neglect.
As for the second part, I don't have a gun in my BOB because I ALWAYS have at least one on me. And, I have no intention of leaving the house if something bad happens. Everything my family would need is HERE. Why would I take a small fraction of things and then go to WHERE? We're not in a flood, hurricane or earhquake zone. Houses are far enough apart that a neighborhood fire wouldn't spread to other homes.
If it's simply a matter of fearing "looters" or civil unrest of some sort, my neighbors are also police officers, current and retired. I'm now on retirement disability after nearly 30 years of service. I have my own plans worked out and I like the idea of staying put.
Others may disagree, but that's my story and I'm sticking to it!
If it's bad enough to leave your house, won't others be leaving also? Wouldn't you think it may be MORE dangerous outside in a vehicle, that offers very little protection. And NO protection agains firearms.