Oh dear, this sounds like a nightmare result. It's like she had a premonition about getting back to the airport. I'm very sorry for the loss of two lives and such pain for the families.
I see a 1:30 am flight to Newark from the Las Americas airport near Santo Domingo, near where the bodies have been found. Santo Domingo Airport Departures
To get to the airport early for check-in, plus return a rental, plus drive 2.5 hours, plus pack, plus check out...they may well have lost track of time while enjoying themselves at the resort, and then were driving too fast to try to make up time.
I see a 1:30 am flight to Newark from the Las Americas airport near Santo Domingo, near where the bodies have been found. Santo Domingo Airport Departures
To get to the airport early for check-in, plus return a rental, plus drive 2.5 hours, plus pack, plus check out...they may well have lost track of time while enjoying themselves at the resort, and then were driving too fast to try to make up time.