Had he been the Kiritsugu of the past, the infamous “Magus Killer”, then he might have been able to forcibly break through this icy bounded field and rush to his daughter’s side. However, the current Kiritsugu had been touched by “Angra Mainyu” and had already been corroded by this curse. His flesh was getting weaker and weaker. His limbs atrophied, his sight began to fade, and he had completely lost the ability to use magecraft. He was not much different from a terminally ill patient. He couldn’t even find the starting point of the bounded field, and could only wander in the blizzard, waiting till death.
He understood all his attempts had been in vain – recently Kiritsugu had already faintly felt that his time was probably up. In other words, he probably hadn’t had much time left since the moment he became cursed by the black mud.