Smith's abuse as a child left him fearful that night, he said. It "was the reason I froze and went along."
Smith initially reported the incident without naming the sergeant, an option permitted in the military for victims of alleged sexual assaults who want to receive counseling but not start a formal investigation.
He changed his mind and filed a formal complaint, launching the criminal case, two months later after a friend told him she had heard the same sergeant had been involved in a similar incident with another airman. The alleged victim later denied to investigators that any wrongdoing had occurred.
"I wanted to move on with my life, but the moment I reported it, it just made things worse," Smith said.
His Air Force medical records show he was considered a suicide risk after he said, "I might as well kill myself." Smith insisted he was only joking, but when the Air Force officials checked his computer, they found online searches on overdosing on cold medicine. He said they were "random searches."
He says that he repeatedly ran into the sergeant he had accused and that the sergeant once laughed at him as he drove past the gatehouse where Smith was working. After he complained of insomnia and anxiety, he was diagnosed with "acute stress reaction."
After he was transferred to Travis to be closer to his family, he was assigned to work in the base chapel. He assisted with memorial services and briefed new arrivals about the chaplain's office.
In a memo in May that recommended against his discharge, Col. Robert R. Cannon, the wing chaplain at Travis, praised Smith as "an outstanding airman" who "embodies the Air Force core values."
Smith's assignment at the chapel was temporary, however, and his commander, Lt. Col. Enrico W. Venditti Jr., turned down his request to be trained for a permanent assignment because he had not yet served two years, as the rules require.
And because Smith was barred from carrying a weapon because of the suicide risk, Venditti also said he could not be a security guard again.
That was fine with Smith. "I have a medical condition that does not allow me to work in the security forces," he told his doctor, according to Air Force records. "I was sexually assaulted by a security forces member. I will take almost any other job."
On Dec. 4, three Air Force doctors agreed at a two-hour hearing at Randolph Air Force Base in San Antonio that Smith should be given a medical discharge.
Smith has asked the Air Force secretary, Deborah Lee James, to overturn the discharge order, his last chance to stay in the service.
"I really feel betrayed," Smith said. "I love the Air Force, and I love being able to serve my country."