Three-week-old sushi merely needs an appreciable amount of wasabi poured over it to mask the taste... of death. It's okay, though, because Chad has eaten marmite before. He can survive anything. That said, it's still pretty gross.
Um... yeah, good thing he used wasabi. I'd of done it for less as long as I had a lot of wasabi, not to mask the taste as much as to kill the bacteria on it.