Crazy as a Soup Sandwich - S3-E29
Other mistake: The actor playing Gus misses lifting a box to throw, and just makes a throwing motion with his empty arms.
Other mistake: Veteran actor Elisha Cook's name is misspelled "Elisa Cook" in the opening credits. (00:01:00)
Answer: Poisoned food, heart attack from eating too much food, or he slipped in the shower. The list is endless.