True, Maria the Ripper was an unequaled Noble Phantasm that delivered instant death in a single blow. All the conditions had been achieved as well—‘night’, ‘within the fog’, and a ‘woman’.
But even if one brought about a phenomenon that twisted cause and effect, a foundation, something to serve as the raw material for it, was still needed.
In this case, Maria the Ripper was, at its essence, a [curse]—the collected grudges of thousands of unborn children. That was the true nature of this fearsome Noble Phantasm.
Accordingly, in order to counter this Noble Phantasm, what was necessary was neither luck nor endurance, but purely an absolute resistance against curses.