Earlier quoted context omitted.
TA mentions that they shipped in construction materials via diplomatic containers.
Yeah. I'm still not sure how to parse the GP's comment, "it created an attack vector of one". On its face, that sounds like a good thing, less attack vectors! I mean, not like sourcing materials locally alleviates things. Apparently the US embassy in Moscow was discovered to have listening devices mixed in the concrete used to construct it...
I think this was the main reason why they shipped construction materials in. And then it makes sense to use containers that are tamper-resistant enough to be able to trust its contents.