I noticed in the photos that there seemed to be no rebar in the concrete or concrete block walls.
Rebar would have made it a bit more difficult to cut their way in.
A neighbor owns a concrete cutting and coring business.
He displays various mementos from unusual jobs, including a concrete-encased I-beam that they cut right through; he said it slows them down and needs more water for cooling.
I noticed in the photos that there seemed to be no rebar in the concrete or concrete block walls.
A descent alarm would have made rebar irrelevant.