That's rather strange, given that I'm sure I remember seeing a picture of her smiling as she swam towards the bears (though I suppose she could be happy at the thought of meeting her end if that is what she wanted).
I'm no expert in these matters but I suspect in her confused mental state she was drawn toward making contact with the bears, rather than wanting them to kill her. Things only changed when she realised- too late- they were not friendly creatures.