Gun Safety
The Federation has a media campaign in hopes of getting civilians to enlist to protect the world from the Arachnid threat. The irony is that in one of the ads, soldiers give children automatic weapons and bullets like candy. They are so cavalier about this that it seems like the army could potentially be the threat to people.
Challenge
Upon arrival to boot camp Diz is challenged by the instructor. She puts her gear down and starts to fight. She's good, getting in a few punches on her superior officer. The irony is though she's tough as nails she isn't ready for war just yet. She gets taken down, and that's the point of boot camp. You have to fight your way out.
Winning
Rico is made squad leader during a boot camp exercise. He's told the high score is 280 and he's expected to beat it. During the exercise one of his men keeps getting in the way because his helmet is blocking his vision. Rico, so adament about wining takes the man's helmet off to fix it. The irony is that because all he wants to do is win he leaves his man vulnerable, and stray bullets cut through his head and kill him.
Nothing to Fight For
Johnny joins the Federation army because of Carmen. He doesn't really want to be in the military, he wants to be with his girl. The irony is that because he didn't have something meaningful to fight for he will easily drop out. And this is the case when one of his men dies in a training exercise. He signs is papers to leave the military. It's not until his parents are killed in Buenos Aires that Johnny has something to fight for.
Running
During a battle on the Arachnid planet one of the troopers runs in fear in order to save her life. The irony is that by running she falls into a sink hole and is carried away and killed by arachnids.