Unity crashes when i get to fight the boss

So have this boss and when i get to fight him, after some seconds the editor crashes.

Here's the log.

The Boss's script:

 using UnityEngine;
 using System.Collections;
 
 public class EntScript : EnemyScripts {
     
     //===========//
     //[VARIABLES]//
     //===========//
 
     public enum Actions{Attack,Walk,Nothing};    // All of the Ent's actions
 
     bool doAction = true;                        // Can the ent do an action?
     Actions currentAction = Actions.Nothing;    // Action the the enemy is preforming
     Vector3 desiredPosition;                    // Position that the enemy will move
 
     //===========//
     //[FUNCTIONS]//
     //===========//
 
     //Attack action
     //This will make the ent shoot in the player's direction
     void Attack(){
         //Plays animation
         GetComponent<Animator> ().SetTrigger ("Attack");
 
         //Look at the player
         Vector3 pos = player.position - transform.position;
         pos.y = 0;
         Quaternion rot = Quaternion.LookRotation (pos);
 
         while (transform.rotation != rot) {
             transform.rotation = Quaternion.Slerp (transform.rotation, rot, Time.deltaTime * 5f);
         }
 
         //Shoot
         Shoot (6,0);
 
         //The enemy is not preforming action
         currentAction = Actions.Nothing;
     }
 
     //Walk action
     //Will make the ent walk to a random position
     void Walk(){
         //Play animation
         GetComponent<Animator> ().SetBool ("Walking",true);
 
         //Chooses a random direction
         if (desiredPosition == Vector3.zero) desiredPosition = ChooseRandomPosition ();
 
         //Walks at the chosen direction
         bool gotToPosition = WalkTo(desiredPosition);
         if (gotToPosition) {
             desiredPosition = Vector3.zero;
             currentAction = Actions.Nothing;
             doAction = true;
         }
     }
 
     //Return a random position
     Vector3 ChooseRandomPosition(){
         Vector3 roomPos = room.transform.position;
         Vector3 pos = new Vector3 (roomPos.x + Random.Range(-4.0f,4.0f),transform.position.y,roomPos.z + Random.Range(-4.0f,4.0f));
         return pos;
     }
 
     //Timer
     IEnumerator Timer(){
         yield return new WaitForSeconds (1f);
         doAction = true;
     }
 
     //Returns a random Action
     Actions GetRandomAction(){
         Actions action;
         action = Random.value > 0.5f ? Actions.Attack : Actions.Walk;
         return action;
     }
 
 
     void FixedUpdate () {
         //If the enemy isn't preforming any actions, choose a action for him.
         if(currentAction == Actions.Nothing&&doAction){
             doAction = false;
             currentAction = GetRandomAction ();
         }
 
         //If the enemy is preforming a action and...
         switch (currentAction){
             //...this action is attacking
             case Actions.Attack:
                 //print ("Attacking");
                 Attack ();
                 StartCoroutine (Timer ());
                 break;
             //...this action is walking
             case Actions.Walk:
                 //print ("Walking");
                 Walk ();
                 break;
 
         }
     }
 }
 

The EnemyScript (the parent of the boss's script)

 using UnityEngine;
 using System.Collections;
 
 public class EnemyScripts : MonoBehaviour {
 
     //===========//
     //[VARIABLES]//
     //===========//
 
     //Public variables
     public int health;                    //Enemy health
     public float speed;                    //Enemy speed
     public int damage;                    //Damage to deal
     public Transform player;            //Player
     public GameObject mesh;                //Mesh to apply damage effet
     public Material damageMat;            //Damage effect material
     public ParticleSystem particles;    //Damage Particles
     public Room room;                    //Room that the enemy is in
     public Transform[] shootPos;        //Shoot positions
     public GameObject[] bullets;        //Bullets that the enemy shoot
     public float bulletSpeed;            //How fast the bullet travel
     public float range;                    //How long the bullet will travel
 
     //Private variables
     //NavMeshAgent navAgent;            S//Mesh agent
 
     //===================//
     //[PRIVATE FUNCTIONS]//
     //===================//
 
     // Apply values
     void Awake(){
         player = GameObject.FindGameObjectWithTag ("Player").transform;
         //navAgent = GetComponent<NavMeshAgent> ();
     }
 
     //Adds red tint to the enemy when he's damaged and instantiates particles
     IEnumerator DamageEffect(){
         //Add material effect
         Material originalMat = mesh.GetComponent<Renderer> ().material;
         mesh.GetComponent<Renderer> ().material = damageMat;
 
         //Add particle effect, if there is one
         if (particles){
             ParticleSystem newParticles = Instantiate (particles,transform.position,transform.rotation) as ParticleSystem;
             Destroy (newParticles.gameObject,1f);
         }
 
         //Change back to the original material
         yield return new WaitForSeconds (0.1f);
         mesh.GetComponent<Renderer> ().material = originalMat;
     }
 
     //Receive Damage
     void ReceiveDamage(int receivedDamage){
         //Take damage
         if (health - receivedDamage >= 0)
             health -= receivedDamage;
         else
             health = 0;
         
         //Add a damage effect
         StartCoroutine (DamageEffect ());
 
         //Check if the enemy died
         if (health == 0) {
             if (room)
                 room.EnemyDied ();
             Destroy (gameObject);
         }
     }
 
     //Deal damage to player
     void OnTriggerStay(Collider other){
         if (other.tag == "Player") {
 
             //Add knockback
             Vector3 dir = other.transform.position - transform.position;
             dir.y = 0;
 
             //Deal damage and apply knockback
             other.gameObject.GetComponent<PlayerScript> ().ReceiveDamage(damage,dir,50f);
         }
     }
 
     //==================//
     //[PUBLIC FUNCTIONS]//
     //==================//
 
     //Shoot projectiles
     public void Shoot(int activeShootPos,int activeBullets){
         //Bullets that the enemy will shoot
         GameObject bullet = bullets [activeBullets];
 
         for (int i = 0; i < activeShootPos; i++) {
             //Where the bullets will come from
             Transform SPos = shootPos [i];
 
             //Creates bullets//
 
             //Instantiate bullet
             GameObject newBullet = (GameObject)Instantiate (bullet,SPos.position,SPos.rotation);
             //Sets the bullet's values
             newBullet.GetComponent<BulletScript> ().bulletSpeed = bulletSpeed;
             newBullet.GetComponent<BulletScript> ().damage = damage;
             //Destroy's the bullet
             Destroy (newBullet,range);
         }
     }
         
     //Walk to a given position
     public bool WalkTo(Vector3 targetPosition){
         //Look at the desired position
         Vector3 pos = targetPosition - transform.position;
         pos.y = 0;
         Quaternion rot = Quaternion.LookRotation (pos);
         transform.rotation = Quaternion.Slerp (transform.rotation,rot,Time.deltaTime*5f);
 
         //Walk to the position
         GetComponent<Rigidbody> ().AddForce (transform.forward*speed);
 
         print ((transform.position - targetPosition).magnitude);
 
         //If the enemy is close to the target position, return true.
         //If not, return false.
         if ((transform.position - targetPosition).magnitude > 2)
             return false;
         else
             return true;
     }
 
     //Attack the player
     public void AttackPlayer(){
         //Looks at the player
         Vector3 pos = player.position - transform.position;
         pos.y = 0;
         Quaternion rot = Quaternion.LookRotation (pos);
         transform.rotation = Quaternion.Slerp (transform.rotation,rot,Time.deltaTime*5f);
 
         //Move's towards the player
         GetComponent<Rigidbody> ().AddForce (transform.forward*speed);
     }
 }