Kazuo Kiriyama gets one when Shou Tsukioka is pursuing him. Shou is stalking Kazuo, convinced that he will win and it'll be easy to shoot him from behind when only them two are left. On the second day, Kazuo goes into a public toilet building that lies in an area that will become a "forbidden zone" at five o'clock - all bomb collars in the area will detonate. Shou listens to Kazuo pissing, confident that he'll soon be done and leave before five. When the pissing sound goes on for several minutes, Shou gets suspicious and slowly goes into the toilet...when it turns out Kazuo made a hole in his water bottle and hung it above the urinal. As Kazuo walks away in the distance, Shou's collar explodes. Ten seconds past five.
Kazuo has yet another awesome moment when he kills Toshinori Oda, who is even more evil than him. Toshinori gets shot by Kazuo, but wears a Bullet Proof Vest under his shirt which keeps him alive. He lets his enemy know he's still alive by faking a death rattle, so Kazuo will walk over to him and check if he's really dead (so Toshinori can shoot him point-blank with his hidden pistol). Toshinori even sniggers quietly and congratulates himself for his clever ruse. Instead, Kazuo looks at the possum-player with a sort of vague amusement and checks if he's alive - by firing dozens of bullets into Toshinori's unprotected cock and balls. Score!
The reasoning behind it's a bit silly, but in the manga the fight with Kiriyama and Sugimura is laced with awesome. One of the greatest moments comes when Sugimura finally finds the rhythm of the fight, dodges Kiriyama's attack with his eyes closed, and ends by slamming Kiriyama into a tree.
Sugimura: Surprise you murdering fuck.
The fact that the Kiriyama/Sugimura fight is as ridiculous as a DBZ episode but still manages to be spectacular is, in itself, a crowner.
Mitsuko's last scene in the movie may also count (if, y'know, you disregard killing Kotohiki), when she absolutely refusesto stay down every time Kiriyama shoots her, which is at least four bullets in the back.
In every version Mitsuko does not give up. When Kiriyama tries to shoot her she still fights back, making her the only girl (besides Noriko) that fought him evenly.
Near the beginning of the film, Sakura Ogawa is one of the first people called to get her supplies and weapon. When the bag is thrown to her, however, she hurls it right back at the soldier, gives him and Kitano a defiant Death Glare, and storms out. She is one of the few people who absolutely refuses to play the game no matter the circumstances. Bad Ass Pacifist indeed.
Shinji's death in the film. He blew himself up ( with a bomb he created himself no less ) to take Kiriyama down with him and to revenge his dead friends. His attempt to hack in the computer system was pretty awesome as well.
When Shogo Kawada is called up to get his supplies and weapon, he has a bag thrown to him by a soldier and walks out the door. Two seconds later, he storms back in, chucks the bag back and grabs another, proclaiming it to be his bag. Considering the guards or even the teacher could have shot him for that insubordination, it just shows how Bad Ass he is.
Although it went by too quickly for the likes of him, the look on Kamon's face as Kawada jams a pencil into his throat is priceless.
When Kazuo Kiriyama, the unstoppable killing machine armed with more guns than the Terminator, who took down more students than anyone else, and even managed to survive a high speed car chase where his vehicle flipped over and was riddled with bullets, is taken down by a single shot to the forehead by Noriko, who, up to that point, hadn't been very action oriented.
When Kazuo Kiriyama takes down multiple students despite initially only having a paper fan in the film.
When Hiroki actually decides to fight, even Kiriyama can't keep up with him.
During the fight, Kiriyama blinds Sugimura in the left eye with one of his own throwing knives. Later, during Shuya's fight with Kiriyama, he uses the throwing knife Sugimura had left with Yukie to give to him to blind Kiriyama in the same eye.