Story Related Achievement.
- Once Arkham Mansion is reached.To defeat Zsaz
& slowly approach the corner of the doorway where the hostage is being held.
to enter corner cover.
Zsaz is hiding behind the hostage, you must wait until the hostage head moves and you get a clear view of Zsaz's head. When this happens press
to do a Batarang quickthrow.
The achievement pops following the cutscene.