Game crashing on startup?

I'm trying to make a game with progressing dialogue. Here's the script I'm using that seems to be causing the problem.

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class CutsceneCtrl1 : MonoBehaviour {
 
     private Text dialogueText;
     private float delay = 5;
     public string[] lines; 
     private bool isFinished;
     
 
     void Start ()
     {
         dialogueText = GetComponent<Text>();
         dialogueText.text = "";
         isFinished = false;
 
     }
 
     void Update()
     {
         foreach (string line in lines)
         {
             dialogueText.text = line;
             while (!isFinished)
             {
                 if (Time.time >= delay)
                 {
                     isFinished = true;
                     delay = Time.time + delay;
                 }
             }
             isFinished = false;
         }
     }
 
 }

Thing is, the game keeps crashing whenever I try and run it. Not sure where the problem is.