The robots never “sleep” for lengthy periods of time; this makes wandering their cities both endlessly fascinating and exhausting. I am especially drawn to these crowded alleys: they are always buzzing with all manner of activity and always in a state of perpetual dusk.
The body will stay where it is, in the dark. The tunnel will keep its secret for now. More importantly, to remove the body would undo, to erase, an important part of their story. Whatever caused their demise is in the past and what we do now will not affect that.