I've had a few sim fires that got out of control to where my sims couldn't put it out, so I got everyone out as quickly as possible. They lost a lot of stuff, but that's all easily replaceable.
When I worked in Assisted Living, we did fire drills probably once a month where we had to get residents outside. Many of them didn't want to budge until they had a shower, got dressed, had their hair done, etc. I had to be firm and let them know that if this was a real fire, they would have burned up by now and that the point is to get out as quickly and safely as possible. Some of them tried to argue with me that it was indecent to be outside in their pajamas and I pointed out that their lives are more important than modesty.