Is more funny after you watch it more than once. Walter put everyone in only two categories. Dependable or not. And if you were in the second category, you likely were a pervert or had some other derogatory trait. No way to know if he just spreading rumors or latched onto one.
I wish more directors made shows like this.
Balloons are open. Most typically do not expand but the excess air just escapes out the bottom. Basically they will rise till the overall weight matches that if what they displace.
There are more efficient balloons that do expand and can attain same great heights. Far more than conventional aircraft even. But that expansion is mostly due to excess material in the construction and little from stretching. Thus the pressure difference is minimal while the volume increase significantly with altitude.