Black Mask and Mad Hatter surveyed their new project - Killer Croc. Tetch had implanted a controller in Croc's head. Croc got some False-Facers into a safe and finally got rid of the implant he'd been scratching at.
Batman found the safe - all the False-Facers had been mutilated. He found the discarded implant and escaped as the police arrived. Batman went to James Gordon's former home (which he bought under an alias) and ran some tests on it.
Batman stopped Croc from eating Tetch. He tried to explain to Croc that he had an infection where the implant was. It had halted his immune system, therefor kicking the mutation Hush gave him into high gear. Batman got a syringe into his tongue. Croc ran; Batman grabbed Mad Hatter.