In Elim Garak’s time as an Obsidian Order operative Dr Parmak was interrogated by Garak after being arrested for being part of an illegal political group, the interrogation was implemented in part as test by Enabran Tain, wanting to be sure his doctor was trustworthy. Parmak was no coward but was rather sensitive and after four hours of Garak staring at him he relented and told them everything he knew.
Parmak was sent to a labor camp for three years. After he was released, he returned to Cardassia and practiced medicine again. (DS9 episode: “The Die is Cast”)
Years later, when Dr. Parmak was working with Garak in the voluntary med unity, he still had trouble making eye contact at first, but the past was soon forgotten and the two became good friends.

