Someone pushes someone over, they bang their head on something and are killed instantly. This seems to be the best way to pull off involuntary manslaughter without making the guy who did it unsympathetic.
Depending on the context, death by falling over may be seen as a particularly "un-dramatic" way to check out. It's fine if the show's realistic (or if the focus is on the 'death by accident' [...] [tvtropes.org]