A lone survivor in a group of Italian tourists killed while scuba diving escaped death in the Maldives Thursday — because she stayed behind on a yacht while her friends took the plunge.

A sixth diver, a student at University of Genoa, never entered the water as the rest of the group dove 160-feet into a cave in Vaavu Atoll Thursday, according to the Italian media outlet  liberoquotidiano.it.

It wasn’t immediately clear why she stayed behind on the yacht, named Duke of York, while the rest of her group explored the underwater cave near the island of Alimatha.

The student, who was not identified, had been geared up to dive when she changed her mind and stayed on board, the outlet reported

She was the “only direct survivor of that day” and  a “key witness for reconstructing the final moments before the accident,” the outlet reported  — though authorities have said there were roughly two dozen other non-crew members on boat over the course of the day Thursday.

Monica Montefalcone, a marine biology professor at the University of Genoa, and her 20-year-old daughter, Giorgia Sommacal, vanished during the scuba trip.

The young woman was headed home to her family Friday,  the outlet reported.

Three other adventure seekers on the trip — Muriel Oddenino of Turin, Gianluca Benedetti of Padua, and Federico Gualtieri of Borgomanero — also failed to resurface from the dive.

Search crews were halted due to rough weather Friday, and local police were investigating.