Time to use 100% foil-backed dry wall and chicken wiire + ferrites
I saw a specification for a high powered pulsed UHF transmitter test 'warehouse'. The main features were that the foil backed dry wall / gypsum panels had to be bonded and areas around the joints and corners covered with 'chicken wire' of certain dimensions. All services, which included water pipes, were also bonded and passed through ferrites.
If these protections can contain a signal, they can equally protect from such signals, IMO.
With respect to American military tests, many in the past have been questioned, especially when the senior officer n charge of projects was, later, hired by the contractor. Boeing has had lots of projects prove unsuccessful after detailed Congressional investigation.
The question what were the attacked buildings constructed from - woos, brick or concrete?
Hell, Boeing couldn't even build a 'high tech' fence designed to stop illegal immigrants from Mexico.