About a Girl - S1-E3
Visible crew/equipment: Right after the opening credits, when Dr. Finn tells Bortus, "I will not perform a sex change on a perfectly healthy newborn," the camera pans to the left as she walks to her desk, and the yellow T-mark can be seen on the floor in her office, where Bortus will stand. (00:03:25)
Answer: The book "Flatland", which is mentioned in the show, is a real book that may answer your questions in full (it's the story of a 3-D being experiencing the 2-D world and the 1-D world). In the 2-D world, there is no height, so there's no way to slice anything in half (horizontally). A being living in the 2-D world sees any object or being as a line (it's messy, but the lines have thickness, just not height, but all thickness is the same). So if the Orville was seen, it would only be seen 2 dimensionally and be seen as a line and others beings could just move out of the way. While there were buildings in "Flatland", perhaps this world doesn't have any, or the Orville didn't bump into any. There is death in "Flatland" when a being isn't careful and is poked, but these are usually by lines and triangles and the Orville would more like the circles and not in danger of poking anything.
Bishop73