Unless it's a toddler up the deep end. We need to correct for "floating" or "sunk".

We don't know, because theberserkingblacksmith didn't tell us if they were ok with this. You could also put the corpse in a water tank next to the pool with a shared water flow, but that's a different experiment. Or else sprinkle the corpse into the pool in tiny bits (i.e. micro corpses) invisible to the eye.

Plus, what if you were led to a leg of an L-shaped pool where, before you were in the building, a researcher might have put a corpse on the other leg of the L, in a way that you cannot see from your vantage point, you might decide to swim, or not swim, in said pool?