Ted: "Oxygen is a corrosive gas, in the same family as fluorine and chlorine, hydrochloric acid, hydrofluoric acid. Essentially, that's why we're breathing helium down here. Because oxygen at any level higher than 2.3 becomes toxic."
Norman: "Can you run that by me again ted. I don't speek balloon."
Ted: "What, Oh that's my voice. You see, the helium resonates differently with my vocal chords."
Harry: "Follow the yellow brick road."