To dream that you are in the lavatory means that you are cleaning yourself while being in various circumstances. The negativity such as bad thoughts and unpleasant relationships are being washed away. If you see the lavatory being dirty and untidy, it means that you should reconsider the people you are surrounded by. Perhaps you chose the wrong company to be with. The lavatory could also represent the fact that you are very judgmental towards the others. If you have an interaction with someone while being in lavatory, it shows the adventurous side of you and your desire for intimacy.
Read more about dreaming of Lavatory in other dream meanings interpretations.