Guide Page: "Whatever Happened to Mr. Garibaldi?" wrote:Londo is very careful with his wording around Cartagia.
Which is why Cartagia likes Londo...he stands up to Cartagia, but does so in such a way that Cartagia can't touch him...doesn't give him any excuse or way in. He's got nowhere to go...and in a way, he admires and respects that.
The above quote, from the Lurker's Guide, kinda makes me wonder if maybe Cartagia's seeming insanity is just him trying to screw around with Londo. When he shows Londo the room with all the heads on it, is his talking to them a show designed specifically to irk Londo off or does he actually talk to them? When he says he wants Centauri Prime to burn so that he might become a living god, is he being serious or is he just joking around with Londo, hoping to make him upset, whilst not telling him what his true intentions or motivations were?
With regard to the latter... it's also possible that maybe, in truth, he's utterly devastated by the news that the Vorlons are on their way, and that he, like the doctors in MASH, can only deal with the horrors he's brought upon himself with his own bizarre form of humor.