Wikus' first encounter with the Nigerians. When it looks like they're about to lop off his arm, he grabs an alien BFG and starts blasting. Then he holds the leader at gunpoint while the goons fetch a pack full of weapons for him. Doubles as a CMOA for the leader, who stares down the barrel of said BFG and doesn't even flinch; he laughs and applauds.
During the attack on MNU, Christopher goes into a Heroic BSOD at the sight of his dissected alien comrades. When Wikus finally snaps him out of it so they can escape, he grabs a pile of parts and builds an explosive on the run.
When the evil MNU Squad Leader shoots the rocket launcher, not at the Wikus's fallen mech, but at the defenseless space ship trying to escape, and Wikus has the mech grab the rocket out of mid-air. (Also seen in the trailers.)
Two words: Telekinetic. Mecha. That explodes people.
Wikus van de Merwe:Is that all you got? Fok you! I'm not scared of you! Fok you! Is that all you've got?!IS THAT ALL YOU'VE GOT?!"
What makes the mini mech battle even better is the fact that Wikus has a chance to escape, but his newly developed conscience won't let him. So he saves Christopher's life and then proceeds to utterly curb stomp the Mooks. And on top of that, you know how he says "I'm not scared of you"? It's clear that that's a lie: he knows perfectly well that if he's captured he'll be tortured, experimented on, and killed. He's terrified out of his mind, but he keeps on fighting anyway. If that's not badass, I don't know what is.
Koobus is telling the CEO his plan to capture Wikus "quietly". The MNU headquarters is then rocked by an explosion. It's Wikus and Christopher, armed with badass alien guns. They then proceed to own the entire MNU security force by themselves.
When the usually calm Christopher yells "FOK!" in his language, it comes as a shock and an awesome, since we have become accustomed to Wikus dealing out the foks.