In my case, the carriage was the last one on the train and the sea of poo was right next to the internal door. I imagine that this incident had only just happened and the company hadn't had time to deal with it yet.

This happened to me in London. I was late for my train and came running down to the platform mere seconds before the due departure time. I forgot I was in the UK and therefore still had plenty of time. Straight away I saw an empty carriage. I knew it was to good to be true, but couldn't help myself. Sure enough, some poor barstard had lost the battle with a large surge of diarrhoea and it covered about a third of the floor. I took a chance and switched carriages. Then watched through the windows as my manouvre was repeated by every other person.