I don't get it. If the Earth is flat, there would be edges. Squares, rectangles, triangles, and even random blobs of matter all have edges. Even if these items have gravity or some sort of magnetism, you could theoretically fall off of any of these edges. The only objects that don’t have edges are spherical. You or whatever you’re traveling in would keep going round it. Whether it’s ball-shaped or egg-shaped doesn’t matter, and neither does the direction you take. You would never get to an edge to fall off of or back away from.