I guess this is a wake up call to everyone that deals with cement in their day to day work.
Could be someone that failed to seal one of their ducts, could be someone that failed to glue a conduit.
Malleable cement has a large horizontal force as well as a vertical force, it will blow out any ducting or conduits that aren't held in place, therefore giving the "molten" cement somewhere to travel.
I was always trained to use a primer AND adhesive on any PVC conduit install, treat it like it is a pressurised water pipe they said.
Let's face it, these days if you're not young, you're old - Red Green