Spoilers!!!!!!! The way Bane "died" (if he did) was done that way on purpose. Kyle had no problem dispatching people with guns or killing them. Batman always said "no guns", he won't kill people. I think Nolan did it to show how anyone can just quickly blow someone away. Catwoman even said something to the effect of how easy that was. Besides, Bane would have easily killed an injured Batman and Catwoman.