The science is in: poison is bad.
In this one, Ian and Liv talk about the Olympic marathon at the 1904 Summer Olympics, which took place in the fine, fine city of St. Louis, Missouri. The marathon was full of unexpected obstacles, such as wild dogs, oncoming traffic, and poison. It's almost like the course was specifically designed to be difficult.
Also, Ian can't imagine the fourth dimension. Liv is running from her inner demons.