Actually, I love the opening of STID exactly because it shows how inexperienced and reckless Kirk still is after a year in the chair. The opening scene is full of stupidity and irresponsible behavior for a leader. Wonderful, deliberate, entertaining, and delightful, stupidity and irresponsibility. A perfect contrast to a 36 year-old TOS Jim Kirk, who would've tried to save those people, too, but not that way. A cock-sure 26 year-old Kirk who "hasn't lost a crewman, yet," would pull exactly that stunt. Kirk always had some hubris and felt invulnerable to varying degrees. But that scene on Nibiru was hubris without temperance, and he may have mixed feeling invulnerable with feeling immortal. Brilliant scene. It actually vindicates all those at the end of ST09 who said he wasn't prepared to captain the Enterprise. From what he did on Nibiru, he probably wasn't.