This is remarkable not only because of the intense amount of heat at .25 solar radii, but also because of the strong gravitational gradient involved. But there is no reason why a large object, made of ice and rubble, should not have a shot at surviving this flight. Imagine melting 10 meters of ice, for example, even with an acetylene welding torch. Clearly it takes time to get the job done. Additionally, the non-volatile solids may help insulate deeper collections of ice.