Brain injuries are just bizarre. I hear about incredible cases in which people survive enormous impact and come out with "scrapes and bruises," but then Natasha Richardson "falls" while skiing, laughs and jokes about it, has no visible signs of an injury, and then just goes brain dead. I technically understand how the brain could have been swelling or bleeding over the time span, but what gets me is the way other people survive such extreme traumas like a gunshot to the head or a Phineas Gage type of injury...
http://en.wikipedia.org/wiki/File:Phineas_Gage_CGI.jpg
ETA: my post reads with a calloused tone, but that's really not how I typed it to sound. More like a shocked train of thought kind of thing. Her poor boys...