I was thinking that the logical key to hit when you really PANIC and need to stop audio would be the ESC key, which is already used for something else. So then I started to wander what other keys could be used…
Since it’s probably not a function that you use very often, it’s not something that you learn as a reflex, which you might need it to be.
So then I thought: Disaster strikes! You must stop all audio as quickly as possible! 
Well, you simply smash the keyboard with both hands with the primordial intent to kill whatever’s making that noise!
So the idea is: Pressing a large enough number of any combinations of keys (say 10-12) is the shortcut to panic.
Yes, what a brilliant idea, I think I have my future as an interface designer laid out before me…
