how to stop rewards for DisplayInterstitialAD

so i have added ads for when u click on Buttons in my main menu new game , continue and quite and also have a button in my pause menu to watch an ad and if you finish the ad you get a life but the issue is when u click in the main menu on new game , continue or quite you are getting rewarded if you watch these ads. I only want the player to be rewarded for clicking on the watch a Ad to get a life button.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Advertisements;
 
 public class UnityMonetization : MonoBehaviour, IUnityAdsListener
 {
     public int livesToGive;
 
     private LevelManager theLevelManager;
 
     public bool ranOnce = false;
 
     string GooglePlay_ID = "3588324";
     bool TestMode = false;
 
     string myPlacementId = "rewardedVideo";
     // Start is called before the first frame update
     void Start()
     {
         Advertisement.AddListener(this);
 
         Advertisement.Initialize(GooglePlay_ID, TestMode);
         
         
     }
 
     public void DisplayInterstitialAD()
     {
        Advertisement.Show();
     }
     public void DisplayVideoAD()
     {
         Advertisement.Show(myPlacementId);
     }
     // Implement IUnityAdsListener interface methods:
     public void OnUnityAdsDidFinish(string placementId, ShowResult showResult)
     {
         theLevelManager = FindObjectOfType<LevelManager>();
         // Define conditional logic for each ad completion status:
         if (showResult == ShowResult.Finished)
         {
             // Reward the user for watching the ad to completion.
             Debug.LogWarning("You Get A Reward.");
 
             if (!ranOnce)
             {
                 ranOnce = true;
                 theLevelManager.addLives(livesToGive);
             }
             
 
 
         }
         else if (showResult == ShowResult.Skipped)
         {
             // Do not reward the user for skipping the ad
             Debug.LogWarning("You Do Not Get A Reward.");
         }
         else if (showResult == ShowResult.Failed)
         {
             Debug.LogWarning("The ad did not finish due to an error.");
         }
     }