Sometimes peeing happens due to fear or the right kind of trauma (I've heard electrocution can cause it). But when death occurs the body relaxes and the bowels will empty. After death your body does a few strange things including emptying whatever is in your intestines.

Fun thing I've noticed when I feed my snakes live rats... The rats almost always pee and poop themselves before they die.

As someone who also loves being the victim I have looked up what happens to your body after death. Even though we can't experience it I love to fantasize I can. There are plenty of informative articles on the subject.

I also learned from a first responder friend of mine that for men if damage occurs to the spinal cord it will immediately cause an erection and that is one way they can tell if a man has suffered a serious spinal injury.

I know that doesn't pertain to you but the more you research these things the more fun stuff you learn! :D I get off on imagining all of it :)