I'm guessing that you have leather car seats? Or plastic? And that it takes a lot more than wipes to get diarrhoea out of fabric-covered seats. I had a Urinary Overload Event in the car once. Sometimes, that last mile to the public toilet is a mile too far. Anyway, that just took water and some nice-smelling disinfectant. Could have been worse. As you already know, of course.