Milbrandt
Muse
I worry a bit about that shuttle / capsule. If the line were to break, do the wheels on that thing have any kind of brake?
I thought about that too: what if it snaps now? Then I saw the cable in an up close shot. It looks pretty thick and strong. Also, they seem to use a pulley (the orange one) to keep the cable from scraping the sides of the shaft (I think that's what it's for). And even if it would break, perhaps the air pressure beneath will keep it from falling too fast. Not too sure about that though.
But I wouldn't worry about that, I guess they thought it through pretty well.