Some tile crawlers scent settlement money. Hence the wailing and gnashing of teeth
I don't think that they'll get far. They did make attempts.
While I'll backseat drive just like KD is, I'm going to follow up that you're depending on prior experience. It's a bit like demanding a woman go out the back door of her house rather than shooting the goblins coming in the front. You might know that the backdoor would have been safe from the after-action reports, but not only didn't the woman know that, it might have honestly not occurred to her.
What about when said mud is actually underwater, it is dark, and the vehicle is 15 ft underwater.
I'd think it was 15 feet into the water - IE 15 feet from the shore.
Also, underwater mud is denser mud, which you'll float on even easier. It's part of why salt water is denser than fresh, as several heavily loaded ships learned to their displeasure when entering a fresh-water source like a river from the ocean.
Buoyant means it floats. If it's submerged, it sank -- not floated.
I think he was trying to say that it provides more buoyancy. Not that it, itself, is more buoyant. IE you'd "float" on it easier than plain water.