Ok all of those are feet because the heels are a distinct visual feature in all of the limbs displayed.
So we can conclude there are 3 people in that stall
Observing the direction the heels are facing we can conclude that the person with the blue socks is facing toward the wall, the person with the white socks is facing toward the the person in the sandals, and the person with the sandals is facing the person with the white socks.
You can also observe the black boots. Since it doesn't make sense to put on boots when you have sandals on, we can conclude the boots are not the person's who is wearing the sandals. Therefore the boots are the person of the blue or white socks
While on topic of footware, notice there are only two sets of footwear present in the photo, but there are three people. This means one person didn't bring their footwear to the stall, but there other one did.
Still on topic of footware, notice that they both have no shoes/boots, letting their socks touch the disgusting sticky pissed floor
Take notice that the person with the blue socks is on tip toes. This implies the person with the blue socks has some reason to elevate the entire body. This can either to reach something on top or to fit or position self so something can be done on the bottom.
Now take notice of the person's legs of white socks. The furthest leg is a slanted incline. For this to allow, the person would need to be sitting.
Notice the thickness of the legs the blue and white sock persons have. Those are nothing compared to the slimmer person wearing the sandals. It is within reason to believe the persons wearing white and blue socks are male and the person wearing the sandals is female.
Now determining the age of persons wearing the white and blue socks is tricky, but not impossible. The biggest and only clue we have is the curve of the muscle in the leg. Taking the curve and comparing it against the
leg of an adult male and a
leg of an a child male,
we can see it more closely resembles that of a child.
Finally, notice that their pants, or underwear is not off showing bellow the stall. This implies they are not butt naked, or just slightly bottom naked.
So finally with all that info, here is what is truly going on:
A mother of two male children is an a store or restaurant and the need to take a leak. They are children, so might still require assistance with their urinal duties, we don't know how trained they are after all, but we will assume stupidly untrained for such mission. However, the mother doesn't want to leave one child alone because she is dumb and paranoid or maybe in a bad neighborhood. In fact, who knows, maybe someone will kidnap little Timmy while he is waiting for them right outside the stall. So she takes both to the stall where she helps one take a leak while the other tries to his best to fit inside and not watch.
So one question remains, why take off the boots and have socks touch the disgusting sticky pissed floor? Well even if what they are doing in the stall is more intimate, you wouldn't want to take off your shows for the socks to touch this shit floor. I have no idea why one would do it.