The premise was the absence of Morrison's interference and assassination.
The Half Moon Association's records mentioned that Jacob, this strangeness, was immune to all exorcism and physical attacks, which meant that he couldn't be eliminated by conventional methods.
This was exactly what Yan Junze excelled at, for he never considered killing the strangeness, but rather sought to find its weakness and resolve it with the correct method.
He had thought everything through: no interference from Morrison, no shortage of energy, no spatial stasis preventing his escape, no oversight whatsoever.
But if Jacob were to be eliminated, the records of the Half Moon Association indicated that this particular strangeness was currently irreplaceable, so its elimination would definitely deliver a fatal blow to the Half Moon Association.