I have seen water in lift shaft many times, mainly comes from upperdeck door area and galley. that part of A/C is too far back to get to the MEC as the nose up pitch will not allow it.
So, instead, it drowns the
Centre Equipment Centre (where the FQUIS, Brake System Control Unit, ADF and Radio Altimeters are)???
Back in the dim, dark past, Radio engineers were constantly having problems with water in the Forward Cargo saturating the CEC racks. Modifications have added an extra layer of protection... but water seems to have found its way through multiple layers of protection in this latest incident.
Rgds.
NSEU