In the early second season, Vir's confidence is only just emerging; though he has been speaking out more since The Geometry of Shadows (which I consider Vir's coming out episode), there is no evidence to suggest that he is at all convinced of his own agency at this point. Indeed, I'm not even sure he has good reason to be so convinced. Remember, after all, how he arrives in Midnight: by all appearances, someone has beaten this young Centauri down. Thus, I agree that here, he is frightened and swept up by events.
I also believe, however, that Vir's developing concern for the state of Londo's soul is also apparent. Otherwise, why be so visibly disappointed? Otherwise, why should Vir phrase his ardent objection in precisely the way he does - not "what you are doing is morally repugnant" (though Vir certainly knows this), but "you can never go back"? Given this concern and what he knows about Londo thus far (and in the narrative, it is Vir who knows more about Londo than any other regular character), I think it is also plausible that Vir would want to preserve Londo's growing trust in his loyalty.
In short: I believe both lines of argument are right. ;)
As for Vir's guilt, I don't think we're meant to see him as entirely innocent. I'm definitely sure Vir doesn't see himself that way. He is, after all, the first Centauri we see apologize to a Narn. Given the way JMS wiggles between portraying the Centauri as "The Declining Roman Empire - IN SPACE!" and "The Third Reich - IN SPACE!", I think we are supposed to read Vir as the decent, patriotic German who gradually - and with horror - realizes that the nation he loves has been hijacked by mass-murdering thugs and grows into heroism as a consequence of this realization. It's a very, er, human narrative - which is why I love it - and Vir - so very much.
(I have a very clear weakness for "loyal" characters of every stripe.)
Regarding Vir's choice to abet Londo -
In the early second season, Vir's confidence is only just emerging; though he has been speaking out more since The Geometry of Shadows (which I consider Vir's coming out episode), there is no evidence to suggest that he is at all convinced of his own agency at this point. Indeed, I'm not even sure he has good reason to be so convinced. Remember, after all, how he arrives in Midnight: by all appearances, someone has beaten this young Centauri down. Thus, I agree that here, he is frightened and swept up by events.
I also believe, however, that Vir's developing concern for the state of Londo's soul is also apparent. Otherwise, why be so visibly disappointed? Otherwise, why should Vir phrase his ardent objection in precisely the way he does - not "what you are doing is morally repugnant" (though Vir certainly knows this), but "you can never go back"? Given this concern and what he knows about Londo thus far (and in the narrative, it is Vir who knows more about Londo than any other regular character), I think it is also plausible that Vir would want to preserve Londo's growing trust in his loyalty.
In short: I believe both lines of argument are right. ;)
As for Vir's guilt, I don't think we're meant to see him as entirely innocent. I'm definitely sure Vir doesn't see himself that way. He is, after all, the first Centauri we see apologize to a Narn. Given the way JMS wiggles between portraying the Centauri as "The Declining Roman Empire - IN SPACE!" and "The Third Reich - IN SPACE!", I think we are supposed to read Vir as the decent, patriotic German who gradually - and with horror - realizes that the nation he loves has been hijacked by mass-murdering thugs and grows into heroism as a consequence of this realization. It's a very, er, human narrative - which is why I love it - and Vir - so very much.
(I have a very clear weakness for "loyal" characters of every stripe.)