The most unnerving thing in this video, is the sound. The sound of the building creeking, and swaying. I think I would be done working in a tall building after riding this one out.
When the video started, I thought, "That little connecting bridge is going to get twisted or completely broken by the earthquake" - which, of course, didn't happen. It worked very well. Is that a walkway? Probably not. I think it's more likely to be something to help stabilize the buildings when they're moving like this in an earthquake.