Is there a possibility to estimate how the inner waterline was in the last 20 minutes? I guess that at 2 AM when the forecastle submerged the grand staircase was flooding from D-deck to C-deck. But how did it keep track in the next 15 minutes until the dome imploded? Was water maybe still rushing down the staircase and fill the lower levels, which means that when the dome collapsed it was still around C-deck? Or did it keep track like it is shown in the 97' movie and the dome collapses when water is between A-deck and Boatdeck level? If so, from where did all the water come from to fill the staircase in such a short time?