Probably a good sign
A tipped-over porta potty is never a good sign. What’s even worse is that a mysterious liquid flowed out of the porta potty and dried on the cement. The OP was wondering whether it was a good sign that there were no footsteps coming from the thing. Yes, OP, it is a good sign.
Imagine how horrible it would be to be the person inside of a fallen porta potty. Actually, it’s best not to imagine such a thing. However, we’re curious how this could have happened. Maybe some punks decided to push the porta potty over for poops and giggles.