Does the low priority queue ever ends?

Im new and i had to left the game, it was some personal reason but, i have been waiting like 20 minutes for the low priority queue to end and it just goes to 5 minutes again and again? I mean its not fear that the game penalizes you if you have to leave the game? For example you are playing and something important happens wth u have to leave. I would like that if you leave the game just let another person join wtf