User blog comment:The.Outsider/Daniel's Part In AC3/ Templars & Assassins Argument/@comment-5019018-20120923203124/@comment-1153722-20120923205327

He 'helped' with the Great Purge by being tied to a medical bed while being half unconscious, being administered some kind of drug called SK-345 and then subconsciously revealing information about the Assassin hideouts when asked about them by Doctor Sung.

He didn't purposefully reveal any information, nor did he do it with his own will. Vidic and Stearns put him through more horrors than anyone else...