Ricin is derived from castor beans. At one time, it was used as a laxative. Due to its antiviral and antimicrobial properties it is used to treat skin infections and allegedly promotes hair growth.
The C-Suite refers to the part of the building where the offices of a company's top-level executives are located: Chief Executive Officer, Chief Financial Officer, Chief Operating Officer etc.
In the original Sherlock Holmes stories, Holmes meets his end when he drops from the Reichenbach [Water]falls in Switzerland. The name of the piece is called "The Adventure of the Final Problem" by Sir Arthur Conan Doyle.
"Simplicity is the ultimate sophistication" is indeed attributable to Leonardo Da Vinci, as stated in the episode.
"When an archer misses the center of the target, he turns around and looks for the cause of his failure within himself" is a line attributed to Confucius.