Make Stamina the "Do things better" button

[Superlagg]

Put in a looping scream that plays as long as you shift scream, and you take oxy damage, hearing loss, and pass out when you scream too much. Also using it too much blows out your voice.

But like why shouldn't I just keep shift held down for all my actions? Chances are I'll have regenerated my stamina in between improvable actions.