Changing a boolean value on button press not acting as expected?

OK, so my feeling is this should be a straight forward but for whatever reason I am getting an odd result. The idea is that on a button press; a boolean variable is changed from false to true. However, when I go to check the value of the bool (after pressing the button) using a debug.log in an update function it returns false, false, false, true every frame. The hope is to use the value as a breaker for a while loop in another part of the code, but I think I need it to be constant true to do so.. Any help would be much appreciated! Also, I can post more of the source code if desired, although the variable isn't in use anywhere else currently.

     private bool stop = false;

     void Update ()
     {
         Debug.Log(stop);
     }
     public void Stop ()
     {     
         stop = true;
     }

Edit: Here is the code in full =] The idea is to collect location data to write to txt, with start (track), stop (Stop) and reset (Reset) buttons.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using System;
 using System.IO;
 using System.Text;
 using UnityEngine.UI;
 
 public class countWithStop : MonoBehaviour {
 
     private int c = 1; // counter used for while time loop
     private int place = 0; // counter used for tracking places
     private string filepath = "/locationdata.txt"; // the designated filepath that location data is written to
     private FileInfo file; // creating an info point for files
     private string placeName; // String of the place numbers for easy wrtiting to .txt
     private string time; // String that holds the time and date
     private float longitude; // current longitude
     private float latitude; // current latitude
     private string location; // used to format the info for the text document
     private StreamWriter locationData; // creates the .txt
     public GameObject timer; // countdown timer object
     public Text currTimer; // countdown timer text
     private int K = 0; // variable used for timer calculation
     private bool running = false;
     private bool stop = false;
 
     void Awake ()
     {    
         Application.targetFrameRate = 30;
     }
 
     void Start () 
     {
         //file = new FileInfo(Application.persistentDataPath + filepath);
         file = new FileInfo(Application.dataPath + filepath);
         PlayerPrefs.SetInt("countrack", K);
         
     }
     
     // Update is called once per frame
     void Update ()
     {
         //latitude = Input.location.lastData.latitude;
         //longitude = Input.location.lastData.longitude;
         Debug.Log(stop);
         latitude = 1;
         longitude = 2;
     }
 
     public void Track () // function called on button press
     {
         
         c = 0; 
         if (place < PlayerPrefs.GetInt ("place")) {
             place = PlayerPrefs.GetInt ("place");
         } 
         place += 1;
         PlayerPrefs.SetInt ("place", place);
 
         if (!file.Exists) {
             locationData = file.CreateText ();
         } else {    
             locationData = file.AppendText();
         }
         timer.SetActive(true);
         StartCoroutine (Counter());
     }
 
     IEnumerator Counter ()
     {
         running = true;
         while (c < 121/*241*/) { // the amount of half seconds needed for desired time
             
     
             if (c % 2 == 0) {
                 K = 60 - (c / 2); // 60 seconds test
                 currTimer.text = K.ToString ();
                 //Debug.Log (K);
             } else {
                 K = 60 - ((c - 1) / 2); // should be 120
                 currTimer.text = K.ToString ();
             }
             placeName = place.ToString ();
             time = DateTime.UtcNow.ToString ();
             c += 1;
             location = placeName + "\t" + time + "\t" + longitude + "\t" + latitude;
             locationData.WriteLine (location);
             //Debug.Log(location);
             yield return new WaitForSeconds (0.5f);
         }
         timer.SetActive(false);
         locationData.Close();
         running = false;
     }
     
     public void Reset ()
     {
         Stop ();
         place = 0;
         PlayerPrefs.DeleteAll ();
         file.Delete ();
     }
 
     public void Stop ()
     {     
         stop = true;
     }
 }