We do not know what level he dropped down to but NORMAL range is 95-100%.
The blood oxygen level indicates how well the body distributes oxygen from the lungs to the cells. Too low and you have HYPOXEMIA. A dangerous condition.
So that is why the duck is now in a critical stage. When the lungs are not doing the job properly nothing else matters.
Will we be told the truth about the duck status? I don't know. Maybe.
