That sounds more and more like an horrifying oversight. You'd think they'd want to know exactly how it happens, why it happens, and how to fix it as quickly and safely as possible. If it happened once, it could easily happen again, even if only in a few decades.

[Hopefully none of them would still be there by then.]

You didn't...? How could they cut off access to a whole other region? Between the boat, the train, the roads that lead there...