A shocking video of a man being dragged off a United Airlines flight covered in his own blood went viral two years ago today—and the man involved has spoken publicly for the first time. In an interview with ABC News, Kentucky doctor David Dao said he “just cried” after seeing the video of himself, and that the incident left him on suicide watch. The doctor doesn't remember much from the incident after bumping his head on the ceiling. "After that, to be honest, I don’t know what happened," he said, adding that he woke up in the hospital with a concussion, lacerations to his mouth and nose, and several missing teeth. He still struggles with sleeping, concentration and balance, he said, and added that he can only run around three miles now despite doing 20 marathons before the incident. United's initial statement labeled Dao as “belligerent,” according to ABC News, but the airline later apologized for the “truly horrific event.” Dao said he decided to speak out for the first time to thank his supporters from around the world.