On September 3, 2014, Kwon was critically injured in a major car accident. The group was returning to Seoul after attending the recording of "KBS Open Concert" in Daegu (and thus completing promotions for "Kiss Kiss"), when at 1:30AM (KST) around Suwon, a vehicle in front of the group's van began skidding due to the rain, and "the back tire of the group's van [fell off]" as the group's manager (who was driving the van) attempted to avoid a collision with the other vehicle. Rainy conditions made the road slippery, which caused the group's van to hydroplane and skid several times before crashing into a protective wall in the vicinity of the Singal Junction on the Yeongdong Expressway. It was reported that none of the van's airbags deployed at the time of impact, while it is unknown if Kwon was wearing a seatbelt at the time of the accident. By the time the paramedics arrived at the scene, Kwon's injuries were so severe that the paramedics were unable to immediately tell who she was. She was immediately taken to The Catholic University of Korea St. Vincent's Hospital, where she was given emergency CPR before being immediately taken into surgery due to suffering severe cranial and abdominal injuries. The surgeons operated on her cranial area three times while also having to resuscitate her via defibrillation during the procedures. In the midst of a fourth procedure (for her back) in her 11th hour of surgery, Kwon's blood pressure began to drop very rapidly, making it unsafe to continue. Thus, she was moved to the intensive care unit, where she remained in critical condition. It was reported that her brain was severely swollen and that she was not regaining consciousness, with the doctors closely monitoring her condition in order safely resume surgery.Her bandmates Ashley and Zuny sustained minor injuries while bandmate Sojung sustained major injuries. Bandmate EunB was killed in the accident. The group's manager and one stylist also sustained minor injuries.Kwon died in the morning of September 7, 2014 in Aju University hospital after being in a coma for several days since the accident.