Quote from Pewable:
Can someone tell me if they can do it? I tried on 360, PS3, unpatched, patch, GOTY, the 2 demos... And I can't get it. But I can have the one on AA EVERYTIME. I am missing something but I don't understand what. If you do, please write how you did! Thanks, driving me crazy since two days now.
Can confirm that it works on Steam version of Arkham City, on kb/m, both versions of the zip, for Batman and Catwoman (and probably Robin too).
Enter any corner cover, tap the aim button, no matter which gadget (the hook has slower animation than batarang) and while Batman takes gadget away, tap aim again and tap exit corner right after that. If camera angle changes, you got it, now just shoot any quickfire gadget. This zip works the same way as when you catch remote batarang.
OR:
Enter a double-sided corner cover, switch side and during the animation tap aim and tap exit cover. This zip works differently from what i have seen.
Make sure you're using right button to exit corner cover – i don't know which one it is on controller, but on keyboard ctrl does that and space does not.