"I'm a failure.. I failed everyone, boss." he dropped to his knees in front of the Clown Prince of Crime himself, dropping his guns.

Scarecrow didn't cooperate... everything backfired. Jonny's biggest fear is to become a worthless bag of trash. All he was doing in his life, and all he ever wanted to do was work with Joker as his right hand man- Gotham was the worst place to survive and with Joker's trust, he could. Now, being affected by the fear gas Scarecrow leashed out, he sees all eyes turned from him, and loud voices in his head, calling him names like 'worthless', 'expendable', 'pathetic'...

He was just a man. Broken- at that. The gas wasn't helping, only serving his distress more. Even without the gas, though, he'd still break down if Joker ever discarded him. He was so scared.