This floating drilling unit has pontoons and columns that, when flooded with seawater, cause the pontoons to submerge to a predetermined depth. It sits low with a large part of its structure under water. Those pontoons are departmentalized , it is not one large pontoon.
If you notice from that pic they are connected to each other, this allows listing to be corrected. All floating rigs can be manually controled, they dont need electricity. If you look at the pic, those grates you see can very well be under water, they often sink it lower in bad weather even to point those grates may be submerged, it lowers its profile and gale force winds have less impact on low structures.
Last the area directly above the grates is a redundant pontoon, it can not be filled with water by the control system or manually. Those four redundant pontoons are capable of keeping the rig on the surface even if the main pontoons are completely filled. Also those pontoons can not be flooded with fire hoses. Damaged in the explosion? highly unlikely if consider those primary pontoons were 60 to 130 feet under water, that much water makes a very good ballistic barrier to flying debri.
The fire fighters action played no role in the rig sinking, no amount of water dumped on it would have any noticible effect.
Seems more likely they are looking for an escape goat to point at. I dont know why it sank, but an explosion damaging it to the point it sank is highly unlikely. Automated fire systems are independant of the electrical grid, they have battery and in most cases pheumatic safe guards that in an emergency close ballast ports. Unless those systems were disabled, and that would have to be done on purpose I see no way it could sink.
I’m not one to yell government did it on purpose but I see no other viable option than to think it was sank and not from an explosion.
The TITANIC was compartmentalized, with hatches to seal off each compartment, virtually guaranteeing the ship could NEVER sink.