Therefore I wouldn't condemn concrete structures in general without knowing what
it is really going on.
One could make the assumption that a lot more people would have gotten out of
the World Trade Center Towers if they would have been made out of poured
concrete instead of steel.
Is it too much to ask that you look around and see what kind of building you're in? Obviously it is not a short-term problem, though in some cases it might be. Most archives cannot choose what kind of buildings they go into -- the LoC's big move to Culpeper being a very recent exception -- and have to make do with some second-hand structure not built for that purpose.
From the photographs it is obvious that the Cologne building was a primarily concrete structure and it failed completely, tunnel or no tunnel. I know of some persons -- particularly in Britain -- that will want to throw a party upon hearing of the destruction of so many of Karl Marx' papers. But I am rather unhappy to hear that Engels' work went down also; he is not as well known, and a rather important figure whose work is not - to my knowledge - exhaustively researched. Retrieval of documents from this rubble will prove difficult if not impossible.
I do a lot of research at universities all over the country and I find myself going in and out of concrete buildings all the time. One archivist in Cologne noted that large cracks appeared in the basement floor not long before the facility came down; one would assume this a good indicator that things are amiss. My last on the subject.