People think if the earth is flat it either terminates shortly after the ice wall, or it never terminates, but it's possible it has an edge, it's just millions of miles away from the ice wall, and the earth has several, whatever you want to call them, pond worlds, each with its own sun(s) or gigantic hydrothermal vent(s)/volcano(es) that melt the otherwise seemingly ubiquitous ice into water, making life possible.
Even if there is an edge, is that all there is?
What's beyond the edge, another disk earth, something else?
What's below it, nothingness, or perhaps the edge is more like a gigantic cliff, with ground, water or something below, it may be so distant and so dark there, that you can't even see what's below or beyond the precipice.