I’ve seen people empty an AK mag in seconds using their index finger and proper handling of the weapon. You sort of pull the weapon into the finger, it fires, recoil resets the trigger group, you’re pulling the weapon back onto the finger, it all happens fast. It isn’t accurate, but it can be done.
Oops!
It's a really bad technique and terribly inaccurate. Not recommended at all. Won't do that again.