Lol, where did he keep the banana though, I mean.. they're in the desert.

Perhaps another panel of Manny asking and TJ just all like wtf.

I don't get it. =(

What's not to get?

Larry grabs a few plasma grenades from the brute he downed, looks at them with interest, then he loses it.
Second panel is grenades flying through the air and the three after that is basically destruction of the incoming banshees in some freak occurance causing all of them to explode and die.

Then, with strange looks from Manny, Larry eats a banana.

Easy!
Also, could open up a storyline where they try and figure out what the hell happened there, kind of like in Firefly when River picks up the gun and downs five guys with her eyes closed.

I demand a loose Mercenaries 2 reference

"Whoah, the UNSC has an Aussie? When do I get to have an Aussie?"