Thoughts on the scenario after completing "Hammers of Fate".

Here's another question I have: remember the cutscene from Heroes in the final mission for the Orcs, where Alaric talks to Biara in the guise of Isabel, and during the conversation, Biara loses her disguise and transforms into her true self (a succubus)? After that, Alaric runs away and says something like, "How could I? I served a succubus, I betrayed Erathia," etc. And yet, after that, he leads his army as if nothing had happened, as if that conversation never took place, and attacks Gothia. How can this be explained? Was his mind so thoroughly controlled? (Sorry if the question is not entirely relevant to the section).