"True, but only in 20/20 hindsight. Nobody expected water to enter the basement."
In most floods, basements get flooded. From small "I've let the bath over-flow" type floods to "once in a century tsunami" type floods, basements flood. It really is that simple and obvious.
"For the first part, pretty much nowhere has such terminals."
Yes, and that's a problem, not an excuse.
" For the second part, the dividing line is a couple of hundred miles away and irrelevant."
Not when the portable generators you need are over that line there because there's been an earthquake locally and it is quicker to fly in those remote ones than get local ones to the plant via the earthquake shot road system.
"A 'flaw' again based on 20/20 hindsight, huge assumptions as to the outcome...."
Sort of, but the trouble is, in a disaster scenario you're unlikely to have much information until its too late, as in this case. So you have a choice to either definitely ruin the reactor (at a huge cost) but definitely avert a major incident, or risk a major incident and risk ruining the reactor. You can't see into the future and so you HAVE to take a gamble. Its a major flaw with (any) centralised power system like nuclear. Big risks for big rewards, assuming you win.