Soldato
There's more to it than just that though...
Eep that's annoying, I hope my sleeping sewer rats don't spontaneously die too
Still thinking the sofa kills people. I was in a warehouse and two guards were sitting on two sofas watching TV. Hitting one of them anywhere with the tranq gun killed them. So again I had to break the game a bit to take him out. I snuck up behind one sofa and blind fired the cattle prod (or whatever it's called) and when the other guy got up to investigate blind fire the prod again to take him out.