After learning that the Midnight Matriarch's neutral aspect was about to be born, Murphy decided not to linger on the Iberian Peninsula any longer.
He needed to hurry back to the Genesis Engine and activate that device. It wasn't just to resume the Creator's interrupted blueprint. More importantly, besides using the energy of creation to feed the hungry demigods, he now had a more important goal.
He wanted to intervene in the shaping and birth of the Midnight Matriarch's neutral aspect before it was "naturally delivered." He would use his bond with it through their shared faith, along with a massive infusion of searing primordial creation energy, to force his way into the process.
He would use the most "orderly" energy in existence to give the Midnight Matriarch—a creature of chaos—an unplanned "redemption into good."
He wasn't trying to turn it completely into a benevolent vampire god. After all, benevolence and the vampire race simply didn't go together. His ultimate goal was to push it into the neutral camp.
Just like Rose now: it didn't matter whether she did good deeds, as long as she kept some basic limits in mind when doing bad ones.
Of course, no matter how you looked at it, what Murphy planned to do sounded a little strange. His intended methods in particular could be understood in two entirely different ways, depending on whether someone was pure-minded or not.
Even though he was preparing to hurry back, he still had to give the last few things that needed doing his full attention.
Given the importance of the several urgent matters on Murphy's plate, he probably wouldn't have time to return to the Kingdom of Castile and "do a second round of repairs" anytime soon.
The Genesis Vanguard was about to reach the Hades of Adel.