Jeff,
Yes, you're more trapped on an upper level, but you're also more secure.
There are few homes with a truly secure lower floor room in which someone on the outside either can't come through a window, or fire through a window, relatively easily, or come from multiple directions.
If I hole up in my bedroom, I control the entire upper floor. Entry through the windows is a lot less certain, and the only door is a bottleneck through which anyone would have to come to get to me.
If worse comes to worse, I can ensure that the hallway is clear, retreat to one of the backbedrooms, and go out the window to the back.
Anyway, that's my take on it.