The phrase "played Judas" is a biblical allusion that refers to betrayal. If you're looking for other ways to express the same meaning, you could use synonyms like double-crossed, backstabbed, sold out, deceived, or turned traitor. Each of these words conveys a sense of treachery or disloyalty, similar to the way that Judas Iscariot betrayed Jesus in the Bible. Depending on the context of your sentence or conversation, some synonyms may work better than others, but they all have the same basic connotation of being a traitor or betrayer.