Batman Arkham Asylum Episode 2: Intensive Treatment Center

"Joker escapes on top of a mobile security cell to Extreme Isolation; he broadcasts a message to Batman from a nearby guard station telling him that Frank Boles, a member of the security team assigned with escorting Joker to his cell, is actually on his side and has captured Gordon. The Joker also warns that if Batman is caught following him, then Gordon will die."