HELP!! Countdown and Timed Door are not synced?

Hello!

So I'm making a Door that stays open for amount of seconds then close with a countdown on it.

The problem is that the countdown is not synced with the door. I tried changing the values of how much time it stays open and closed and same for the countdown but it is not working..

When the timer resets from 0 third time and forth time the doors are opening open at 10 seconds and not at 9 seconds.

Is there any script that I can make the countdown stop on 0 when the door is closed and restart for 10 seconds for example when the doors are back open ? I'm new on Roblox Studio so I don't know much..

Thanks!!

Here is the video:

https://imgur.com/a/bhcPCpE