Perhaps your deep consciousness thinks that you will definitely not be invaded by dirty things like toilets, which can be found in your past life mentality.
You might as well think about it. Did you ever have confidence that you wouldn't be hurt by those dirty things?
If this was the case before, it means that your subconscious mind may be more demanding, and it is often in this excitement when sleeping. I often have such dreams because of my worries and past experiences.
I suggest you review your self-confidence requirement that you won't be hurt by dirty things such as toilets, and reduce your inner excitement about this problem, so that similar dreams will gradually decrease and life will be normal.