They will be able to evacuate it in 15 minutes because no one will be in the building. If they somehow manage to get it built it will be a financial failure.
They are not copying the burj. You couldn’t even do that since they’re in different seismic and wind regions. The area is actually fairly low on seismic hazards, so I don’t know why they’d test to a 9.0. That model didn’t look properly scaled, fwiw.
Welding is very common in structural engineering.
The company in question prefabs EVERYTHING including the duct work.
So while the construction time is impressive it doesn’t include pouring the foundation or the time spent in the factory. It’s like building a B-24 in an hour. All the stuff that goes into it was built ahead of time.