Exit button doesnt work after executeing ping command but does before doing so (tkinter)

So im very new to python and I'm basically trying to make a program were the user inputs a targets IP and then presses a button below to Execute the command (start the pinging process) and this I've done successfully but now I wanted to add an exit button below to stop the pinging process but I've got a problem. The button works fine before you press execute (works as intended it closes the application window) but when the script is running the button doesn't work at all and just kinda crashes the window but keeps the command running. How can I make the button work att all times (make it work when the script is running).

import tkinter as tk #import tkinter and tkinter library
from tkinter import ttk #package to style widget
import subprocess

def window(): #runs the window ??? i think
    #address = input("Enter Ip Here:")
    subprocess.call(f"ping {text.get()} -t -l 65500")

# root window
root = tk.Tk() # root?
root.geometry('200x200')   #window size
root.resizable(False, False) # makes window non rezisable
root.title('Ping Of Death') #window title

var = tk.StringVar #variable tkinter = StringVar

text = tk.Entry(root,textvariable=var, width = 25)
text.pack()


# execute button
execute_button = ttk.Button( #defines the execute button
    root,
    text='Execute', #defines the text on the button
    command=window
)

execute_button.pack( #package for button
    ipadx=5, #x size
    ipady=5, #y size
    expand=True # ???
)




exit_button = ttk.Button(
    root, text="Exit" ,
    command=root.quit
    )

exit_button.pack(pady=20)




root.mainloop() #to keep everything in a loop