I'm here in Vientiane getting ready for visa pickup. If I am not present when my number is called, but still come before closing, will my visa be voided?

I am number 573 and close to the end so I'm planning on arriving at 2:30pm. But just in case my number has already been called, will my visa be voided the moment I miss, or would I still be able to pick it up at 2:30pm even if my number is called?

Thanks!