Melle script, enemy destroyed without mouse command once in range.

so everything was working till i realized once i got in range of an enemy it got destroyed, i think this has something to do with the fact that i may not have it set up so mouse 1 apply's damage and instead what happens is it sends out a message apply damage once a frame once i get within 1.5 units of the enemy.

here is the Melle script:

 #pragma strict
 
 var Damage : int = 50;
 var Distance : float;
 var MaxDistance : float = 1.5;
 
 function Update ()
 {
     if (Input.GetButtonDown("Fire1"))
     
         var Hit : RaycastHit;
         if (Physics.Raycast (transform.position, transform.TransformDirection(Vector3.forward), Hit))
         
             Distance=Hit.distance;
             if (Distance < MaxDistance)
             
                 (
                 Hit.transform.SendMessage("ApplyDamage", Damage, SendMessageOptions.DontRequireReceiver)
                 );
 }

and here is the script attached the enemy:

 #pragma strict
 
 var Health = 100;
 
 function Update ()
 {
     if (Health <= 0)
         {
         Dead();
         }
 }
 
 function ApplyDamage (Damage : int)
 {
 Health -= Damage;
 }
 
 function Dead()
 {
     Destroy (gameObject);
 }

As well as my 'Fire 1' settings

can someone help please?