If there was a major crankcase explosion it is likely that the cooling water system was damaged and leaking into the hot engine or fire, if there was a fire, generating large quantities of steam (white smoke).
I have seen this on 2 ships where we had the main engine piston seize and crack the liner, the whole engine room disappeared in a cloud of steam.
I can not imagine Class permitting a ship to be built where the main Generator sets can not be started manually, locally. In a blackout situation there is no problem with synchronising the genny onto the board, because the board is dead. You only have to run up the D/A and bang the breaker in manually.
Possibly the crew were unable to isolate the cooling for the damaged generator and therefore could not run any of the generators because of lack of cooling??
Martin was saying this was a large open plan Engine Room, with little attention paid to survivability, so I do not suppose there were two seperated cooling systems installed, with half the engines on each, as there would be on a DP2 ship.
From the Cruise Directors Blog I thought the lifts were working and that there was power on the bridge for the emergency equipment presumably supplied from the emergency D/A.
It is always better to ask a stupid question than to do a stupid thing.