Both were taken to jail because they didn't have Mexican insurance. Later they went to a hospital. The rider, a hull technician was pretty battered, but would recover. Troy was transferred to the Navy hospital where he would die. I saw a training film once that showed how most accidents don't happen by themselves.
Several things combine.
Troy was riding without a helmet. He had been drinking for several hours. He was riding in an unfamiliar area late at night. He took a wrong turn. Now that I think about it, he took a number of wrong turns, beginning with mixing booze and a bike.