Zooming animation doesn't work

Hello,

I have this script that is supposed to play the "zooming" animation ONCE when I have the right mouse button pressed. However, it keeps playing the animation again and again, as long as I have the button pressed. Any help?

This is my script: (and yes, I have set the animation "Zoom" to Once!)

 #pragma strict
 
 var running : boolean;
 var zooming : boolean;
 
 function Update () {
 
     if( (Input.GetAxis("Horizontal") || Input.GetAxis("Vertical")) && !running )
     {
         animation.CrossFade("Walking", 0.2);
     }
     else if( (Input.GetAxis("Horizontal") || Input.GetAxis("Vertical")) && running )
     {
         animation.CrossFade("Running", 0.2);
     }
     
     if( Input.GetMouseButtonDown(1) )
     {
         zooming = true;
     }
     if( Input.GetMouseButtonUp(1) )
     {
         zooming = false;
     }
     if(zooming)
     {
         animation.Play("Zoom");
     }
     
     if(Input.anyKey == false)
     {
         animation.CrossFade("Idle", 0.2);
     }
     
     if(Input.GetButton("Run"))
     {
         running = true;
     }
     else
     {
         running = false;
     }
 }