A lot of people naturally are going to think holy shit, but this is even worse than what people can imagine. They did this in CHINA, where every little piece they stepped on was a risk of collapsing. The one part at a little before 4:20 where the guy goes to grab the grate and it just comes off, I would be surprised if that was the first time something like that happened. If they did this in New York it would still be scary, but not many people will realize or appreciate the fact that they did this in China makes it 100x scarier. It's not just a risk of loosing your footing or grip, but the actual piece you're stepping or grabbing breaking.