In Monster, Roberto mocks Tenma, saying he would never shoot him as doctor's job is to give life, not to take it. He is then proven VERY wrong by the good doctor.
As for Roberto? His crowning moment comes when he comes back from that. Think for a second: he took two bullets, fell off a balcony, and was left to die in a fire in a show where Anyone Can Die and survived. What's more is that he then signs up to be Tenma's defense attourney just to rub it in his face while he sits behind bars. That's why he's the Implacable Man, folks
Well, the fact that Roberto can't use his right hand anymore is a crowning moment all by itself.
Also, the Inspector gets one when he tries to capture Tenma, is stabbed in the side by a murderer, heads after Tenma anyway, as Tenma locks the doors to his car. The Inspector smashes into the window, and looks about to break in until he slides down. When Tenma lets him in? He handcuffs Tenma. (And refuses to unlock them, even though Tenma can save his life.)
Inspector Lunge gets an even more awesome moment near the end of the series: After a close range gunfight between the two, Roberto throws Lunge in a corner and begins strangling him. Just when it looks like Lunge is down for the count, the Inspector grabs Roberto and forces his thumb into his bullet wound, letting him gain the upper hand and giving him the opportunity to make the bastard eat his pistol. Best. Fight. Ever. It's like two Falcon Punches colliding.
Calculations?!... Those calculations don't add up in my head.
Lunge is consistently awesome, even when his behaviour is downright despicable. Crowning moments of funny/awesomeness/cruelty incurred when Lunge drives a suspect to suicide, when he doesn't even bat an eyelid when his wife and daughter leave him or even more so when he later casually turns down the one opportunity to meet his daughter and new grandchild, just because he thought it might help him get into Dr. Tenma's mind set. He rubs salt in the wound by actually smiling to himself afterwards for making such a decision.
This is quickly followed by some awesome Big Damn Heroism when she single handedly rescues Deiter and Otto from a burning building.
Said Nazi crime lord also gets one for keeping his cool throughout the whole scene with Nina, going so far as to completely deadpan his request for fresh underwear.
Let's not forget her Aikido submission of the gardener at the Heidelberg Castle.
Dr. Reichwein demonstrating to two much bigger and younger thugs (who have been hired by Roberto and, possibly Johan) to never disrespect your elders. Especially when said elder can break your nose with their skull. This also qualifies the good doctor as a Cool Old Guy.
This particular crowning moment gets bonus points because a very sympathetic character (Richard Brown) had just been killed by Johan. Reichwein's fight arguably gives the audience a brief outlet for any anger they might have over Richard's death.
And let us not forget his brilliantly executed escape from everyone's favorite Psycho for Hire Roberto. Best. Tea Making. Ever.
Followed by Tenma making his triumphant return after disappearing for four episodes in a row, shooting at Roberto just as he gets a bead on Reichweinn and allowing the doctor to escape.
Grimmer—when he doesn't make us sob like little child, that is.
The people whom Tenma has helped, doing their damnedest to somehow help him. (This may also count as a Crowning Moment of Heartwarming.) It's heartening to know that even with all the people who make it a Crapsack World, there are still good people like Dr. Tenma. Hell, the fact that the manga even shows us the continuing lives of the people he's helped—as opposed to just helping them and moving on—is possibly a CMoA for the manga itself.
Even Dieter has his CMoA, when he walks into a bar full of guys. They mock him for being a kid and one orders an alcoholic drink for him (possibly a martini, given the fruit in it). Dieter takes it, drinks it in one shot, puts the olive in his mouth, raises his hand in a cool fashion and silently walks out. Unbeknownst to the speechless men in the bar, he vomits outside and is disgusted by the drink.
I'd actually say that Dieter's CMoA is when he saves the Turkish district from burning down using Heckel's carpet.
Not to mention that basically every scene that focuses on Dieter is a Crowning Moment of Heartwarming, especially the scene where he decides to stay with Tenma.
And then there's his breaking through the conditioning Johan has put one of the orphans he's watching through, then saving him from falling off a roof.
Johan has a bunch, though they could probably be better described as crowning moments of terror. But the most impressive is likely when, after orchestrating a huge fire in a public library during a ceremony that many of the areas most important businessmen (that he had a hand in organizing, of course) attended, killing a good few, Tenma corners him. At which point, Johan simply raises a finger and points to his own forehead, and smiles to him as he leaves through the smoke and flames, confident that he won't take a life. Even his.
It might not be just confidence. By that point he was already planning his perfect suicide: he may have simply not cared if he died right then and there.
Johan didn't plan his suicide, until a long time after the library burned down.
Let's be fair. Being killed by Tenma would be too perfect and would likely drive Tenma mad. He told his acolytes, "Tenma would kill [him]." Johan likes to play Xanatos Speed-chess, he changes his plans.
Another moment is when he kills Smug SnakeBlue Sophie/fake "Margot Langer." Okay, so technically the one who kills her was Roberto, but still it qualifies.
He had planned on her attempted blackmail days maybe even weeks ahead of time.
Johan's reaction to stumbling upon and reading "The Nameless Monster" once again.
Eva gets one when she truly joins the hunt for Johan after Martin's death. And another when she shoots the ear off of Johan's acolyte, Christof.
Tenma goes to a neo-nazi bar. Four guys attack him. He grabs a ball point pen. He gets all the information he asks for.
Don't forget Martin. His gunning down The Baby's men so that Eva can escape definitely qualifies for this trope. When he finally gets that fatal shot in the stomach, his reaction is to call his assailant an idiot for not aiming for the head. Not just awesome, but badass as well.
The Baby: Threatened by Christoph, who has already killed at least four people and is roughly twice his size. His reaction: keeps his cool and threatens him right back; doesn't even change his stern facial expression while doing so.
Grimmer's little speech to Bonaparta about how Kinderheim screwed up his life along with his insistence that Bonaparta should live just so he can reveal the truth about the horrible, horrible things he did was pure awesomeness.