I've always thought about this in terms of natural disasters or some other situation where the shit hits the fan for everyone. With Hurricane Sandy, my plan was to grab my hiking backpack and bike. That would allow me to get away from the area and be somewhat self-sufficient while supplies and aid were in high demand.
I had kind of a trial run on 9/11 and what I actually took was my IDs and such (was already wearing pants), a bottle of water, a leftover sandwich, the library book I was reading (Because apparently I was like, "Oh, a terrorist attack. I might get bored."), and my glasses. In hindsight, I should have grabbed my contact lens case too, because while contact lens solution was easy to come by, I could not find a case for love or money.
For a fire situation, I dunno, I have a hard time figuring it out. It's not that I'm not attached to my stuff, it's that I'm attached equally to all of it so nothing super stands out. Or the stuff that I'd particularly like to save is large or gets used every day so it's not practical to have it in a separate container ready to go or in a fireproof thing. Like, I'm really sentimentally attached to my plants, but there's no way I can save them. And I don't value my stuff just qua stuff but also for the memory of how I got it But this thread has impressed on my mind that I should consider getting a safe for some of the obvious stuff like memory cards (although I feel like the heat might scramble them?).