Not Dying help

hello i have this script that controls the players health and does most things relating to the player but when the player reaches 0 health he doesn't die can someone please help me here is the script.

 using UnityEngine;
 
 /// <summary>
 /// Class responsible for controlling player's life.
 /// </summary>
 public class HealthController : MonoBehaviour
 {
     [HideInInspector]
     public float CurrentHP; // Current amount of Hp.
     public float maxHP = 100; // Max amount of Hp.
 
     public bool regenerate; // Will Hp regenerate over time?
     public float regenerationSpeed = 5; // Regeneration rate.
 
     public float delayToRegenerate = 5; // Delay to start regenerating.
     private float nextRegenerationTime = 0;
 
     [Space()]
     //public AudioClip[] hitSounds;
     public AudioClip heartBeat; // When life gets too low, it plays the sound of heartbeats.
 
     [Header("Fall Damage")]
     public float heightThreshold = 5.0f;  // The max height that player can fall without hurting yourself.
     public float damageMultiplier = 4.0f;  // The damage multiplier increases the damage in the fall, to make it more realistic.
 
     public AudioManager audioManager; // The audio manager.
     public PlayerUI ui; // The player UI.
     public CameraAnimations cameraAnim;
     public CameraEffects cameraEffects;
 
     private float higherHeight = 0.0f;  // Distance to the ground of the last fall.
 
     private MoveController mController; // The player.
     private CapsuleCollider capsuleCol; // The player collider.
 
     // Use this for initialization
     private void Start ()
     {
         mController = GetComponent<MoveController>();
         capsuleCol = GetComponent<CapsuleCollider>();
 
         // Player starts with max hit points.
         CurrentHP = maxHP;
     }
     
     // Update is called once per frame
     private void Update ()
     {
         CheckFalling(); // Checks if player is falling.
 
         CurrentHP = Mathf.Clamp(CurrentHP, 0, maxHP); // Prevents the amount of hp from being less than 0 or greater than the maximum of HP.
 
         audioManager.isDying = CurrentHP < maxHP * 0.35f; // If the current life is less than 30% of the total, enables the low life effect on the audio manager.
 
         // If the current life is less than 30% of the total, it starts to play the sound of heartbeat.
         if (CurrentHP < maxHP * 0.3f)
             audioManager.PlayHeartbeatSound(heartBeat, CurrentHP, maxHP * 0.3f);
 
         // Regenerates Hp
         if (regenerate && CurrentHP < maxHP && CurrentHP > 0 && nextRegenerationTime < Time.time)
             CurrentHP += Time.deltaTime * regenerationSpeed;
     }
 
     /// <summary>
     /// Applies the damage of an explosion to the player.
     /// Parameters: The explosion damage, the explosion intensity and direction.
     /// </summary>
     public void ExplosionDamage (float damage, float intensity, Vector3 dir)
     {
         ApplyDamage(damage);
         ui.ShowDamageIndicator(dir);
         cameraEffects.ExplosionEffect(intensity);
         cameraAnim.ExplosionShakeCamera(100 * intensity, intensity, 3);
     }
 
     /// <summary>
     /// Applies the damage of a shot on the player.
     /// Parameters: Shot damage and direction.
     /// </summary>
     public void BulletDamage (float damage, Vector3 dir)
     {
         ApplyDamage(damage);
         ui.ShowDamageIndicator(dir);
         cameraAnim.HitShake();
     }
 
     /// <summary>
     /// Applies damage from melee attack.
     /// Parameters: Melee attack damage and direction.
     /// </summary>
     public void MeleeDamage (float damage, Vector3 dir)
     {
         ApplyDamage(damage);
         ui.ShowDamageIndicator(dir);
         cameraAnim.HitShake();
     }
 
     /// <summary>
     /// Apply fall damage.
     /// Parameters: The fall damage.
     /// </summary>
     public void FallDamage (float damage)
     {
         ApplyDamage(damage);
         ui.ShowCircularIndicator();
     }
 
     /// <summary>
     /// Applies damage to the player.
     /// Parameters: The amount of Hp the player will lose.
     /// </summary>
     private void ApplyDamage (float damage)
     {
         if (CurrentHP > 0 && damage > 0)
         {
             CurrentHP -= damage;
             ui.ShowHitScreen();
         }
         nextRegenerationTime = Time.time + delayToRegenerate;
     }
 
     /// <summary>
     /// Checks if player is falling.
     /// </summary>
     private void CheckFalling ()
     {
         // If the player is touching the ground.
         if (mController.Grounded && higherHeight > 0.0f)
         {
             // If the height of the drop is greater than the limit, Applies damage to the player.
             if (higherHeight > heightThreshold)
             {
                 FallDamage(Mathf.Round(damageMultiplier * -Physics.gravity.y * (higherHeight - heightThreshold)));
                 cameraAnim.FallShake ();
             }
             else if (higherHeight >= mController.jumpForce / 6.2f)
             {
                 // Shakes the camera when hit the ground.
                 if (cameraAnim != null)
                     cameraAnim.FallShake ();
             }
 
             // Reset the value to be able to calculate a new fall.
             higherHeight = 0.0f;
         }
         else if (!mController.Grounded)
         {
             // Calculates the distance to the ground and takes the longest distance (the highest point that you have fallen).
             if (CheckDistanceBelow() > higherHeight)
                 higherHeight = CheckDistanceBelow();
         }
     }
 
     /// <summary>
     /// Calculates the distance from the current position to a surface near the bottom of the player.
     /// </summary>
     public float CheckDistanceBelow()
     {
         RaycastHit hit = new RaycastHit();
         if (Physics.SphereCast(transform.position, capsuleCol.radius, Vector3.down, out hit, heightThreshold * 10))
         {
             return hit.distance;
         }
         else
         {
             // If the distance is too big, returns a big value that when the player hit the ground will die instantly.
             return heightThreshold * 10;
         }
     }
 }