[Well, okay, just because he was warm on alcohol, though not drunk. Besides, it didn't even have to be particularly believable.]

Off the top of my head, they thought that capturing a duke wasn't enough, and they were of the opinion that the honor guard should be made to turn on each other, make it all seem like it was an inside job and no one left alive to say otherwise. They had it planned to the minute, but then higher ups vetoed it and the team just stole the duke away without anyone noticing for some hours.