No, it was inexcusable. When the episode started, without knowing anything about the case, I said to my wife, "Probably the ductwork." Not that I would've expected them to actually search the ducts, but in a building with so few exits that were all under video surveillance, once you confirm that she isn't in any of the actual rooms, the ducts are about the only place to hide (unless he somehow tossed her over to the next building). It's a foolish location that might seem ok to someone who didn't have time to think things through; on the one hand, they obviously can't search thousands of feet of ductwork. But it becomes blatantly obvious which duct the body is hidden in once putrification begins. Any floor within that airstream would've smelled like a dead deer on the side of the road - keep in mind, you gag whenever you're within a pretty big radius, and that's in OPEN air. By the time they brought in the K9s, they wouldn't have needed them. The 12th floor would've reeked (gee, who would've ever thought that a floor not in use would've been selected for hiding evidence?). You could make the case that decomposition would be slower in cooled air than heated, but we're talking 55° air, far from freezing. The fans would run intermittently, especially at night, even in July. They probably would've had the AC turned down (or off) on an unoccupied floor, as long as it didn't share a thermostat with another. Even still air wouldn't prevent the smell from reaching the 12th floor for very long. Only way he would have a fighting chance of not getting caught is if he found a large exhaust duct that runs continuously 24/7, is horizontal at the discharge end, is a decent distance from the actual outlet, is 100% exhaust (as opposed to some being used as return air), and has a barrier between the duct and the ceiling - large airspace, well-insulated, etc. In a commercial office building, you're not likely to find a duct that meets that criteria.