My Own Spin On The "Fear-O-Meter" Idea Thread - The Rising mod for Half-Life 2

What if the game looked for certain behaviours from the player that would indicate fear and then affect the game mechanics as a result. Some of the behaviours that are easy to recognise and common in a frightened player are; frantic mouse movement/key presses, sudden drops in accuracy of shots etc.
When behaviours such as these are recognised, the game could do things to intensify the pressure, for example; Play scarier/more intense music, play a heavy breathing sound, play sound effects to make them jump (e.g. wind, a sudden snapping branch they could've stepped on), a filter effect to intensify the atmosphere etc.
I know that the fear-o-meter wasn't originally my idea, but perhaps this spin on it will be better recieved.

Thanks, and keep up the great work.