Enter our protagonist, still slogging along halfway through the third novel of a sci-fi series. He's steadfastly out-Schwarzeneggered Arnold himself, doing everything but leaping suitless from a space shuttle onto an enemy cruiser to bring it down with his bare hands. He's always more cunning, lucky, plucky and derring-do'able than any antagonist alive (or dead reincarnated).
In one scene, he's racing to the rescue down a hallway, running faster than any other creature except the dreaded slarn. At the last moment he spies a microscopically thin wire stretched across at ankle-height that will sever his feet and leave him pounding along on stumps.
He LEAPS and clears the wire, leaving the toe of his heavy leather boot behind. He stumbles, falls, and the bad guy pounces. The struggle ensues and our guy is left helpless, near-paralyzed, on his back. Seconds before the villain delivers the killing stroke, the hero with his off-hand fumbles in his pocket and activates a thumbnail-size gas grenade and flicks it into the air whereupon it explodes, instantly rendering the evil dude unconscious.
Never in two-and-a-half books did the author ever mention such a gadget, or why our hero 24-7 (Earth time) carries them in his pocket.
This is reader abuse, actually capable of causing brain convulsions. There should be a warning on the book cover. BTW, this is an eight-book series, published on Amazon. Names withheld to leave the guilty in obscurity.