I have a couple dha that I would consider using. They are long & sharp enough to stab as well as slash, so I don't see working in a confined space as too much of a problem.
But, I probably would pick up my Paul Chen niu wei dao, because it is sharp, heavy and scary-looking. Plus, I wouldn't care if it got bent or broken (not likely), or rusty, or happened to wack some innocent wall or piece of furniture.
The beauty of using a sword versus a knife is the intimidation factor. Imagine being a cat burgler expecting to run into somone with maybe a bat or gulf club, and instead finding some wild-eyed nut waving a big sword.
No need to shed blood, but you might have to clean up a puddle of something else on the floor.
Keep a piece of writing paper handy, and casually slice it in two for his/her benefit, just to add to the fun.