The fourth and final Aperture Laboratories investment opportunity video is here, harping on the benefits of not having Chell's shins forced into her nasal cavity when falling from great heights.
You don't want your shins inside of your nasal cavities. You do not even want The Shins inside your nasal cavity, which is probably why Aperture Laboratories discontinued work on the ill-fated nose phones to work on something a bit more productive.
Chell finally gets a chance to shine in a video series that until now has been dominated by robots. Robots are fine when it comes to testing out panels, turrets, and trust issues, but when it comes to shattered bones, you can't beat a human hard enough.