Even in dirt rookies sole purpose was to allow the dying ODST to tell his story. The Rookie isn't a character. He's a plot device, and he's got no personality [i]to[/i] build off of. Sometimes people die. It doesn't matter how badass they are. Some soldiers have taken on hundreds of people in real life, only to get shot dead in another battle same as any other mook. It happens. It wasn't a -blam!- you because his death served an important purpose by bringing the squad back together as he had in his game.