The Aztecs would be statted as natives.
I'm interested by what "fighting insects and undergrowth" would be like, game-wise. A few wandering encounters with giant insects would be the literal interpretation, and could have been exciting. I suspect, though, that insects and undergrowth only created negative modifiers to their travel time -- which is also interesting, because I can't think of a game where bugs slowed overland movement before, as plausible to me as that sounds.
Also note the cliche of the rope bridge. Gotta have one of those at least once in a campaign!
But what I really like about this page is how it shows the way to disarm a gunman. Years ago, I read a Johnny Quest comic book that showed this exact same method. Glad to see it again!
There's really no game-related lesson here, though; I just wanted to share I was really digging this story.
There's really no game reason to have the fire engine swerve and crash; it seems like flavor text the Editor added to ratchet up the tension.
(Scans courtesy of Comic Book Plus.)