Why does only one Object stop the timer

Hey, I am trying to make a timer that stops when a enemy hits the player.
The problem is that the timer only stops if one specific enemy hits the player.
Code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Timer : MonoBehaviour
{
    public bool stopTimer = false;
    public float timeStart;
    public Text textBox;

    void Start()
    {

        textBox.text = timeStart.ToString("F2");
    }

    void Update()
    {

        if (stopTimer != true)
        {

        timeStart += Time.deltaTime;
        textBox.text = timeStart.ToString("F2");
        }else {

            textBox.text = timeStart.ToString("F2");
        }
    }

    void OnCollisionEnter2D(Collision2D col){

        if (col.gameObject.tag == "Player")
        {

            stopTimer = true;
        }
    }
}

If multiple enemies have this script attached to them and are all using the Text component they would override each other. For example if Enemy A’s timer is 10 and Enemy B’s timer is 5 and they are using the same text box they would fight over the text box’s text value. One enemy would override the text’s value. You could create a script on the text box itself and call a function there when an enemy collides with the player instead to prevent the overriding.