We recommend that you use the bathrooms in the terminal or the ones outside next to the tent before joining the queue. If you leave the queue to go to the toilet, you are basically giving up your place. You may then have to join the back of the queue when you return, which would be a waste of your time. If you are travelling with other people, you could ask them to save your place. But you will still need to let other queueing travellers know that you were ahead of them in the queue.