My game crashes when the enemy makes contact with the player

I'm trying to make the the enemies in my scene damage my player when they come within a certain range of the player, but every time the the enemy comes within this range unity crashes and is frozen to my screen, i am unable to close the window forcing me to restart my computer. I have built the game but it still crashes however a window comes up telling me that the program is not responding and i am able to close the program. I have tried using a collision to damage the player but i had the same problem.

Here is my code:

(Character's script)

 using UnityEngine;
 using System.Collections;
 
 public class CharacterSetup : MonoBehaviour {
 
     public float characterHealth;
     public float amountOfDamage;
     public bool isBeingAttacked;
     public CharacterShoot CharShoot;
     public CharacterMovement CharMove;
     public CapsuleCollider playerCol;
     public MeleEnemyAi[] MeleEnemyAiArray;
     public GameObject [] MeleEnemies;
 
     // Use this for initialization
     void Start () {
     
         playerCol = GetComponent<CapsuleCollider> ();
         CharMove = GetComponent<CharacterMovement> ();
         CharShoot = GetComponent<CharacterShoot> ();
 
         CharMove.enabled = true;
         CharShoot.enabled = true;
         this.enabled = true;
 
     }
     
     // Update is called once per frame
     void Update () {
 
         MeleEnemies = GameObject.FindGameObjectsWithTag ("Mele Enemy");
         MeleEnemyAiArray = new MeleEnemyAi[MeleEnemies.Length];
 
 
         for (int i = 0; i < MeleEnemies.Length; i++) {
             MeleEnemyAiArray [i] = MeleEnemies [i].GetComponent<MeleEnemyAi> ();
         }
 
         while (isBeingAttacked == true) {
             Deducthealth ();
         }
 
         if (characterHealth <= 0) {
             Die ();
         }
     
     }
     void Deducthealth(){
         characterHealth -= amountOfDamage; 
     }
 
     void Die(){
         print ("You have been killed!!!");
         CharMove.enabled = false;
         CharShoot.enabled = false;
         this.enabled = false;
         playerCol.enabled = false;
 
     }
 }
 

(Enemy's script)

 using UnityEngine;
 using System.Collections;
 
 public class MeleEnemyAi : MonoBehaviour {
 
     public float fpsTargetDistance;
     public float enemyLookDistance;
     public float attackDistance;
     public float enemyMovementSpeed;
     public float enemyAttackSpeed;
     public float damping;
     public float enemyDamage;
     public GameObject fpsTarget;
     public GameObject centreOfScene;
     public CharacterSetup CharSetup;
     public bool isAttackingPlayer;
     Rigidbody rigidbody;
     Renderer myRenderer;
 
     // Use this for initialization
     void Start () {
         myRenderer = GetComponent<Renderer> ();
         rigidbody = GetComponent<Rigidbody> ();
         fpsTarget = GameObject.FindWithTag ("Player");
         centreOfScene = GameObject.Find ("centreOfScene");
         CharSetup = fpsTarget.GetComponent<CharacterSetup> ();
         isAttackingPlayer = false;
 
     }
     
     // Update is called once per frame
 
     void Update(){
         while (fpsTargetDistance <= 2) {
             attackPlayer ();
         }
     }
 
     void FixedUpdate () {
         fpsTargetDistance = Vector3.Distance (fpsTarget.transform.position, transform.position);
 
         if (fpsTargetDistance < enemyLookDistance) {
             myRenderer.material.color = Color.yellow;
             lookAtPlayer ();
             //print ("The enemy can see you");
         } else {
             walkToCentre ();
         }
 
         if (fpsTargetDistance < attackDistance) {
             myRenderer.material.color = Color.red;
             RunToPlayer ();
             //print ("The enemy is attacking you");
         } else {
             myRenderer.material.color = Color.blue;
         }
     }
 
     void OnCollisionEnter(Collision col){
         if (col.gameObject.name == "Player") {
             attackPlayer ();
         }
     }
 
     void lookAtPlayer (){
         Quaternion rotation = Quaternion.LookRotation(fpsTarget.transform.position - transform.position);
         transform.rotation = Quaternion.Slerp (transform.rotation, rotation, Time.deltaTime * damping);
     }
 
     void RunToPlayer (){
         rigidbody.AddForce (transform.forward * enemyAttackSpeed);
     }
 
     void walkToCentre(){
         Quaternion rot = Quaternion.LookRotation (centreOfScene.transform.position - transform.position);
         transform.rotation = Quaternion.Slerp (transform.rotation, rot, Time.deltaTime * damping);
 
         rigidbody.AddForce (transform.forward * enemyMovementSpeed);
     }
 
     void attackPlayer(){
         CharSetup.isBeingAttacked = true;
         CharSetup.amountOfDamage = enemyDamage;
         isAttackingPlayer = true;
     }
 }

As you can see i tried to store the enemies in an array so that the player's script could could check the isAttackingPlayer bool on the enemy's script but i couldn't figure out how to reference the isAttackingPlayer bool. I'm new enough to unity so maybe i'm just doing something really stupid, please help me.