The shadow of the table is unfortunate, as it looks as if it's part of the stain. It isn't. The stain is that line where, if someone had soiled themself, it would leak out.
Here's a stain I saw on the floor in a hospital room:
I don't know what that is or which orifice or other hole it flowed out of, but it's an alarming sight when you're about to go for an operation.
Some stains, you really don't want to see.