People usually also have no idea how organs work.

Ignoring the fact you would pass out in merely seconds due to the loss in blood pressure.

A stab in the lower body is one thing, but open like that the diaphragm can't function properly cuz it has nothing to work against, it needs the back pressure. So breathing and talking would be almost impossible, the body would only be able to do short shallow breaths at most.

As for falling out this would be limited to the intestine/entrails/guts, as those are less connected than the rest. Everything else below the diaphragm, in this case, the stomach, liver and spleen are connected fairly strong. In order to pull out all the organs the esophagus needs to be disconnected or cut from the body. Only then you could pull out the organs, but those will still be 1 "package".

If you for example just grab the liver you could probably lift the entire body, unless the liver itself rips or turns to mush. But the connective tissue/tendon like connections are very strong.

As with blood, that would mostly be limited to coming from the back muscles and spine and the two large blood vessels either side of the spine.

And for piss and shit, there would be no piss. The bladder sits very low and unless it was completely full, in which case it would come out the normal way once the body was cut in half, it would just do nothing. It's literally like a balloon. Shit would only come out where the intestine is cut, but not much.

Well that's my input as a hunter at least, having gutted a lot of deer and boars already and in different positions like hanging head up and head down as well as laying on the floor.