Having read the whole story, I can't help but think that he knew he was transporting drugs, but was duped into thinking he was doing it for the real Milani. Like all the best movie cons, you make the mark believe they're on the inside, but they're really not.
Getting back to the egotism: This is speculation, but I think his thought process on the drug smuggling probably went like this: "I'm so much smarter than everyone else I've ever met, of COURSE I will get away with it, especially with my airtight excuse if I am caught." This kind of reminds me of Hans Reiser, whose egotism and belief in his own superiority was also his downfall.
Getting back to the egotism: This is speculation, but I think his thought process on the drug smuggling probably went like this: "I'm so much smarter than everyone else I've ever met, of COURSE I will get away with it, especially with my airtight excuse if I am caught." This kind of reminds me of Hans Reiser, whose egotism and belief in his own superiority was also his downfall.