But in doing so, she suffered severe burns on about 80 per cent of her body, and is now fighting for her life in the hospital.
Her boyfriend, Jonathan Long, 29, was driving the BMW that slammed into a Tanjong Pagar shophouse early Saturday morning (Feb 13).
The couple is understood to have applied for a flat recently.
Oh is a former Singapore Airlines air stewardess, and also sang getai (a live stage performer during the Chinese Ghost Festival) on occasion.
Witnesses said the car caught fire within seconds of the crash.
Akira Chan, 21, a friend of the group, told ST that Oh was not in the car at the time, but rushed forward immediately to the burning wreck.
"She tried to open the door and was injured in the process," he said.
"She was trying to save her fiance."
Despite Oh's efforts, Long died at the scene with the four other men who were with him in the car.
Oh was conscious when taken to Singapore General Hospital (SGH) shortly after the crash at about 5.40am.
A spokesman for SGH said she is now in critical condition in the intensive care unit.
It was previously reported that Oh, who was born in Malaysia, began singing getai at the age of 16, and studied at a local polytechnic.
She said in a 2013 interview with ST, while a polytechnic student, that she performed to earn money for school fees so she could lighten her father's financial burden.
Getai organiser Aaron Tan, 45, told ST on Saturday he remembered meeting her during a flight in 2019, and that he last engaged her to perform in a virtual getai show last August.
"She started singing getai before becoming a flight stewardess, but kept mostly a low profile," he told ST.
"She had to stop for a while because of her new work commitments, but started performing again last year because of the pandemic."
He described Oh as a quiet and petite person who appeared to be timid, but was actually very independent and had a big heart.
Tan added: "As a getai community, we were shocked to hear of the news, and pray that she recovers.
"She did what she did for love, and it was a selfless act that not everybody could do. It was a commendable thing." - The Straits Times/ANN