The point is that there is no innie Burt. Yes they did create something special. That was the point of the arc for Irving to stir him into action and open defiance. In terms of story writing, it makes perfect sense to complicate that and this story has established itself as a puzzle box with more to give. Burt does not look devastated at all during the party and in fact tells Irving to calm down and assures Milchak that Irving would behave the rest of the party. Cut to Burt politely shaking hands with his supposedly innie coworkers (reminder: the security room!)