This time half a year was not enough, but took closer to one full one:

You fume celestial force and utter the words 'Sanctum circum' (holy bolt) 
Saints smile over you as UNBOUNDED amount of energy merges into your spell.
Surges of holy force coil around your crucifix of St. Kaaymeth forming a
pulsing bolt of divine energy. You twist your wrist and bolt hurls through the
air detonating on Zombie-cop.
Zombie-cop stops existing in this reality.
Zombie-cop is DEAD, R.I.P.
You feel more pure and closer to Las.

86% now.