Jose, I admire your attempt to fight for literally every underdog in this competition, and much like my attempt at defending Cole against Juggernaut, I want to agree with you. Much like I want to agree that Invisible Woman can defeat Goku. You make creative points that in my mind I could see happening. At the very least you're making the tournament more interesting.
But let's face it...it's Inspector Gadget against Frank "The Punisher" Castle. In the words of the great German philosopher Martin Heidegger,
"a man who knows he's going to die and who knows in the big picture his actions will count for nothing, but who pursues his course because this is what he has chosen to do." Or, in the more iconic warning of Shepherd Book of Firefly/Serenity fame, he's what we consider "a believer". Maybe Castle believes this tournament is a quick way to vengeance; his only and ever-pressing goal in life? Maybe Gadget is just getting in his way on a man-hunt to "off" the Joker? He's mostly robot anyways, not a whole lot of moral conviction.
Frank Castle does not eat, and he does not sleep without thinking about his slightly warped sense of justice.
Kill,
kill,
kill,
kill,
kill.... He's like Ryback; Gadget his Jinder Mahal. You might think you have a window of opportunity. You might think you a chance at living through this fight. But the reality is there's a cannon pointed at your heart. You're actually already dead, but your brain hasn't totally stopped working, projecting the last image you remember before the lights finally go out...