What should you say to a person that knocks on a public toilet door while you are doing your business and demands you to leave?

So, I had sat down on the seat of a public toilet just a few seconds ago, when someone knocked on the door and told me to get up and leave in an annoyed tone.

I told them there was another toilet down the hall, they should go there. The person then told me “No, YOU should go there, I am here with a CHILD.”

I told them I simply could not get up at the moment. And they told me “Yes, you CAN. I am here with a CHILD. Children come first”.

What do you do in a situation like that…?

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