Or him not wanting to get caught. I personally favor the view that the eye is rebellious and not the arbiter but some weird mix up. Imagine that instead of evolving from the 3rd and 4th apostles the eye actually devolved into a crude form of the arbiter.
And the motive about the 3rd & 4th apostles being different was something i believe everyone caught onto but no one knew why. We do not see any 1st & 2nd apostle mixes or light & dark, creation & destruction etc. They all make someone their "Chosen" spawn for assumed resurrection/avatar control of that person.