International operations may be different
Passenger counts are important in the evert of crash and fire rescue the emergency responders will continue their efforts until every passenger in accounted for.
Since we do not have the training or authorization to declare a person dead then attempts to rescue, resuscitate will continue until the aide responders are completely exhausted or are relieved from their duties by the trained medical responders. The patient would likely be moved into the galley, or aisle between the lavatories (lavatories closed obviously) to facilitate efforts.
With the thousands of people alof at any given moment medical emergencies are fairly common. Not all such events end well for the person going through the trauma.