The Dark Knight Trilogy: 10 Moments That Make No Damn Sense
5. The Bit Where Gordon Is Not As We Know Him
Gordon is fearless and bold, but hes not stupid. So quite why he decides to go all lone wolf when he hears there's something going on down in the sewer system under Gotham is beyond the realms of logic. He is the Police Commissioner, not a detective, or a whole squad of officers (as would have been more suitable) and he has no right going down there on his own. It's hardly the responsible behaviour of someone you'd entrust the care and safety of your streets to.
Inevitably, he ends up knocked out and taken to Bane, before being shot and half-drowned (he is apparently Gotham's other superhero) and finds himself carted off to hospital for pretty much the rest of the movie.
This is not the Gordon we'd seen: he is logical, fastidious and calm to a fault, and though he has been emotionally and morally broken by the deception of Gotham for its own good, there's no explanation why he would abandon every instinct and principle to go down the rabbit hole. We're supposed to believe he is the wrong leader for peace time, but that exchange, outlining Matthew Modine's ambitions, simply reinforces why he wouldn't make such rash decisions - "he's... a war hero."
It's another case of a character being betrayed for the good of the narrative.