Water should still be flowing over the edge because ice is not impermeable, even large ice sheets several kilometres thick still have water flowing underneath and/or through it. Also, what is keeping the ice wall in place? Firstly, sea ice does not freeze all the way down to the ocean floor, because as you descend through the water, the pressure increases which alters the freezing point of water. Secondly, if it did reach the ocean floor, how can it be strong enough to withstand the vast pressure of all the ocean's water, especially if there isn't anything on the other side of the ice wall to support it? Surely, the high stresses and strains caused from the shear volume of water pushing against the ice wall would cause it to shear, and slip? Finally, what is keeping the rock below the ice wall in place? Rocks are not solid on the macro scale, as even mountain ranges such as the Himalayas behave in a fluid like motion (the vast weight of the orogenic belt results in the range acting like a blob of treacle which starts to spread outwards under its own weight), only at a very high viscosity. I fail to see how the underlying lithosphere, and asthenosphere can suddenly end laterally. The immense pressures and shears would cause the earth to keep on thinning until it competely dispersed itself (mountains would be impossible to form).