[unnouinceput]

It's more then that in this case. She had not vital signs at all, heart not beating and providing oxygen included.

[pc86]

The brain was provided oxygen, just not by her heart.

[meowface]

Also, perhaps during such a cold state more cells are able to stay alive despite having less oxygen to work with? Maybe due to a reduction in how much energy they use or need per unit time? Just speculating.

[heavyset_go]

Cell death is a metabolic process and it can be arrested if overall metabolism is arrested, as well.

[Teandw]

It's important to note that she had no 'detectable' vital signs. Not that she didn't have any vital signs.

Very important difference.