Since the shower tub is very low, maybe the water ran down the curtain and the curtain wasn't in the tub, but just outside the tub.
People have put up plastic on the edges of the shower floor to stop the curtain from getting outside and water running on the floor.
Model X19H Expandable
GMC Sierra Pick up
Been a camper since I was a kid, and that was a long time ago :)
From pup tents with no floors, to tents with floors and flies, to a pop up, to the expandable.