I really like this. You can definitely feel the tension of the life and death situation of this unlucky soldier. I think part of that has to do with the fact that you can't see the soldiers' faces. Minifig faces automatically make any scene like this cute and comical. But not here.
My one minor criticism would be the 'fancy' border you've built. Don't get me wrong, you've built it quite nicely and it looks great, but it kind of takes away from the feeling of fear and tension of seeing someone fall through ice. Perhaps if it was all white, and 'jagged', to kind of mimic what the edges of an iceberg would look like. I just think the blue border kind of takes away from the scene, and is almost distracting.
Overall, it's well done. Good job!