> you must have spare underpants in your suitcase in your room, right? I forgot to mention, that it must've been one of their jobs to figure out which pair of

> you must have spare underpants in your suitcase in your room, right? I forgot to mention, that it must've been one of their jobs to figure out which pair of underpants he will be wearing the next day, i.e. which pair from presumably a few he had in the suitcase is the last clean pair. Ah, the glamorous job of a KGB/FSB agent. Interestingly, I wonder if it meant he could only be targetted the day before he got on a long plane trip... otherwise he might put on the pair too early, get sick while still on the ground, and manage to get to a hospital.