[Python] Python message box showing without stopping script

I have an script that create numbers randomly, between 5 and 55, in a infinite loop. My goal is to show a message box when the number 55 is created. I have try easygui, tkinter, ctypes,... and I have been able to create the message box, but when this box appears the loop stops and it doesn't continue untill the user clicks de OK button. Is there a way to show a message box without stopping the script?

I have been looking for information in forums but I haven't found someone with this problem, so I hope someone can help me.

This is the part of the code with the loop:

def contador():
for x in range(1):
aleatorio = random.randint(1,11)*5
if aleatorio ==55:
estado = "Red"
ctypes.windll.user32.MessageBoxW(0, u"Error", u"Error", 0)
elif aleatorio >=30:
estado = "Red"

else:
estado = "Green"

global t
t = threading.Timer(15.0, contador)
t.start()

t = threading.Timer(15.0, contador)
t.start()

Continue reading...