question:  Explain Mia’s reasons for referring to herself as “hell on wheels.” What is an example of this?
context: The ancient rule was sink or swim—swim in the miasma of a planet without spaceflight, or sink to utter destruction! [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, July 1963. I The horses and packs were loaded before we went aboard the scoutship. Planets make me feel wretched. Either your arches and calves ache or every time you step you think you're going to trip on a piece of fluff and break your neck. A planet is all right for a Mud-eater, but not for me. We have a place in the Ship like that—the Third Level—but it's only a thousand square miles and any time it gets on your nerves you can go up a level or down a level and be back in civilization. They don't care what order you go in, so Jimmy D. jumped up, grabbed his gear and then led his horse down the ramp. I'm hell on wheels. The ship lifted impersonally away from Ninc and me like a rising bird, and in just a moment it was gone. When the sun disappears, somehow you wonder in your stomach if it's really going to come back. And I've seen things that looked good that I couldn't keep on my stomach. One of the smartest moves in history was to include horses when they dropped the colonies. I say "they" because, while we did the actual dropping, the idea originated with the whole evac plan back on Earth. Considering how short a time it was in which the colonies were established, there was not time to set up industry, so they had to have draft animals. One of the eight, as well as the two that were being built then, went up with everything else in the Solar System in 2041. I don't know how many of those planets had animals that could have been substituted but, even if they had, they would have had to be domesticated from scratch. That much water makes me nervous, and roads have to go somewhere.
output:  Mia is tough. An example of this is when she was able to strong arm her way out of trouble with Horst and his gang.
options:  Mia is fast. An example of this is when Mia rode Ninc away from the free breeders as fast as she could.  Mia is frightened. An example of this is when she was approached by Horst and his gang for the second time, which scared her to the point of losing control of her mission.  Mia is mean. An example of this is when she refused to agree to partner up with Jimmy after they returned from their mission.  Mia is tough. An example of this is when she was able to strong arm her way out of trouble with Horst and his gang.