When trying to figure out a puzzle in a booby trapped penthouse, a clue leads Mac and Stella to two vases. Stella then uses a wet finger to make one of them vibrate or sing, and says that a crystal vase will sing while a glass one won't. This is false as glass vases do indeed sing when this method is used.
When solving the final puzzle, Mac correctly leads the team to the grandfather clock. However, he uses a key to restart the clock. Keys are used to rewind spring clocks. Grandfather clocks don't require a key and are stopped and started with the pendulum only, as they are powered by the weights.
When testing the two vases, Stella says that crystal isn't glass. It is glass. Glass is a generic name, while, crystal is a subcategory of glass, made in the same manner as glass but with different materials. Hence, all crystal is glass, but not all glass is crystal.
Stella and Mac discuss how the body is perfectly preserved because the apartment was sealed and dry, and that's why there's no rodent or insect activity, because nice and bugs couldn't get in. Yet as they walk from room to room, the whole apartment is covered in cobwebs.