,How do I detect if there are no more enemies of a type in an area?

Helloo, I have a small room filled with a few enemies. There are doors on either side of the room, they're supposed to close when the player enters the room and there are still enemies inside, then the doors should reopen when there are no more enemies in the room.

I currently have a large box collider that covers the whole room and have an OnTriggerStay script that detects whether there are any enemies left in the room. Problem is, since I'm using tags to identify them, what I think is happening is that the game is identifying 1 random enemy from the whole scene with the "hazard" (enemy) tag. This means if the identified enemy is outside of the combat room, the player just gets locked in permanently. My code is extremely messy at the moment, I've been awake way too long.

 public class CombatRoom : MonoBehaviour
  {
      // Start is called before the first frame update
      void Start()
      {
  
      }
  
      // Update is called once per frame
      void Update()
      {
          
      }
  
      private void OnTriggerStay(Collider Hazard)
      {
          if (Hazard.gameObject.tag == "Hazard")
          {
              GameObject.Find("CombatDoor").GetComponent<CombatDoor>().EnemyState = 1;
              Debug.Log("enemy in");
          }
          if (Hazard.gameObject.tag != "Hazard")
          {
              GameObject.Find("CombatDoor").GetComponent<CombatDoor>().EnemyState = 0;
          }
      }
  }

Also since this way of doing it is so broken I had to detect the player colliding with the same collision box on a different script. I imagine there's a much better way to do this, maybe 'foreach' loops? But I've never used them. Please help!