It took me a while, but I figured out that there were two different timelines being shown simultaneously. The light bulb went off when I was trying to reconcile how TMIB could be traveling with (and subsequently bleeding out) Lawrence to save Teddy, while William and Logan were with the same host, then operating under the identity of El Lazo in Pariah.
I'm working on the assumption at this point, that Logan actually ends up getting killed by a host that's gone "haywire." As a result, William does go "black hat" and through his position with the family's "company" who has invested in the Delos/Westworld Park gets unfettered access to the park. (William's fiance/wife is Logan's sister.) The references to events that happened 30+ yrs ago, could not only refer to Arnold's death, but something that happened in the park that Delos covered up, which could logically lead to a conclusion a host(s) doing something that directly lead to the death of a park patron.
So whatever initial "affection" William/TMIB had for Doloros, he comes crashing to his senses and now recognizes the "hosts" as anything but human and thus has no moral qualms about doing anything he wants to them. But also believes that Arnold created something much deeper within the park (the ultimate easter egg?) and he's trying to crack that part of the mystery that will lead him to the maze and the answers he's looking for.
