I worked neuro-trauma ICU for several years....they haven't released details but likely a couple scenarios:
1st,that she had an aneurism(no head smack)that ruptured(or an arterio-venous malformation)that ruptured slowly,causing her to fall/pass out, seemingly recover, then wammm, her time was up - once that blood inflitrates the brain,its like pouring water on a battery........from a medical viewpoint,watching it happen,helplessly,as I have, its horrible...
2nd - she took a smack on the head and hit in a freakishly vulnerable spot - like the temple, mid temple between temple and ear, or another part where the skull is softer, cracked a bone,hit an artery ,or more likely,since it was slow, a smaller vessel...got up and walked around,then the leak sped up and got her....I've had pts in on observation,and then there was nothing we could do to save them....its likely whats called an epidural hematoma - bleeding within a dangerous part of the brain..
I was heavy hearted all day...my friends in NY said the transplant folks had arrived on Monday night, so likely the family is going to have this beautiful woman live on and save the lives of so many other suffering people...
Liam Neeson always seemed so tickled by his family,he must be a broken man......GOD-how tragic!!!Never gets easier to hear things like this does it?
In my years in the unit,we saw plenty of injuries with and without helmuts....but the ones who wore helmuts always.....always actually recovered.....in my time there anyway....