Can't figure out While Loop crash?

I am creating a turn-based grid combat system for my dungeon crawler and have run into an issue with the enemy turns. Each enemy has "x" amount of total ap, they use it each time they move. I have created a While(enemy.apCur > 0) loop but for some reason, it crashes/freezes the game. I have tried running it without the while loop and the movement properly subtracts 1ap when the enemy moves, but for some reason, there is a crash somewhere along the way when it is in a while loop. The reason I want to do this in a while loop is because I want the current enemy to exhaust all of its AP before moving onto the next enemy's turn... currently, all the enemies take their turns in unison without the While loop.

There is a bunch of systems working within my scripts so I will try and cut out the info that is unnecessary within the scripts for ease of readability. First, my combat manager's ChooseNextInLine() function is called to choose the next enemy/player in the turn order (which is determined when the combat is initiated):

 public void ChooseNextInLine()
 {
     GameObject curEntity = _turnOrder.Dequeue();
 
     if (curEntity.GetComponent<PlayerManager>() != null) //PLAYER
     {
         _turnOrder.Enqueue(curEntity);
         PlayerCombatTurn();
     }
     else if (curEntity.GetComponent<ClassEnemy>() != null) //ENEMY
     {
         ClassEnemy curEnemy = curEntity.GetComponent<ClassEnemy>();
 
         _turnOrder.Enqueue(curEntity);
         EnemyCombatTurn(curEnemy);
     }
 }

The enemy combat is then called:

         enemy.apCur = enemy.apMax;
 
         while (enemy.apCur > 0)
         {
             if (!enemy.isMoving)
             {
                 enemy.apCur--;
 
                 bool tileSelected = false;
                 Vector3[] possibleTiles = enemy.surroundingTiles.ToArray();
 
                 //RANDOMIZE THE ARRAY ORDER
                 for (int q = 0; q < enemy.surroundingTiles.Count; q++)
                 {
                     int rand = RandomNumberGenerator.Instance.rndCombat.Next(enemy.surroundingTiles.Count);
                     Vector3 temp = possibleTiles[rand];
 
                     possibleTiles[rand] = possibleTiles[q];
                     possibleTiles[q] = temp;
 
                 }
                 //LOOK FOR A TILE TO MOVE TO
                 foreach (Vector3 tile in possibleTiles)
                 {
                     if (!combatOccupiedTiles.Contains(tile) && combatActiveTiles.Contains(tile))
                     {
                         tileSelected = true;
 
                         enemy.targetPos = tile;
 
                         enemy.MovingTurn();
                         break;
                     }
                 }
 
                 if (!tileSelected)
                 {
                     print("No tile selected");
                 }
             }
         }
         enemy.isMoving = false; //Failsafe bool assignment
         ChooseNextInLine();

The enemy.MovingTurn() function runs a coroutine that Lerps the enemy from its current position to the targetPos. At the beginning of the coroutine enemy.isMoving is set to true, and at the end it is set to false. I believe it is somewhere in here that there is an issue, but I can't figure out where. Here is the appropriate script:

 public IEnumerator MoveToPosition(Vector3 targetPos)
     {
         float time = 0f; //Reset timer
         _parentEnemy.isMoving = true;
 
         //MOVE THE PLAYER
         while (time < 1)
         {
             time += Time.deltaTime / (GameManager.Instance.enemyTurnTime); //How much time has passed relatively 
             transform.position = Vector3.Lerp(curPos, targetPos, time);
             yield return null;
         }
 
         transform.position = targetPos;
         AddSurroundingTiles();
     }
 
     public void AddSurroundingTiles()
     {
         //SET VECTORS
         curPos = transform.position;
         _parentEnemy.curPos = curPos;
 
         _parentEnemy.surroundingTiles.Clear();
 
         //FIND NEW SURROUNDING TILES
         _parentEnemy.surroundingTiles.Add(new Vector3(curPos.x, curPos.y + 1, curPos.z)); //UP
         _parentEnemy.surroundingTiles.Add(new Vector3(curPos.x, curPos.y - 1, curPos.z)); //DOWN
         _parentEnemy.surroundingTiles.Add(new Vector3(curPos.x + 1, curPos.y, curPos.z)); //RIGHT
         _parentEnemy.surroundingTiles.Add(new Vector3(curPos.x - 1, curPos.y, curPos.z)); //LEFT
 
         _parentEnemy.isMoving = false;
     }

Any help would be greatly appreciated, thanks!