Also, maybe it's just shorthand for "inflict Harm," but "rain down hell" is pretty non-specific. The results of moves need to be spelled out explicitly in a way that gives them a mechanical effect. That effect doesn't need to always be the same thing, and should absolutely offer the MC lots of options, but the effect needs to be concrete.
If you want to introduce both crazy hi-tech and a SkyNet-like system that is trying to prevent people from using it, why not try the following:
Item: Crazy-Hi-Tech Gizmo: Left over from before the apocalypse and intended for gods-only-know-what, Crazy-Hi-Tech Gizmos have both a Power (+1 to +3) and an associated Move. So for instance, you might have a "tricorder" that gives +2 to Read a Sitch rolls, a "psychotropic lens-o-tron" that gives you +1 to Read a Person, or a "sub-sonic dopamine actuator" that gives you +2 to Seduce or Manipulate rolls. Or an "pheromonal dominance projector" that makes it terrifying whenever you Go Aggro on someone. Or whatever.
Now your custom move for SkyNet is: Under the Watchful Eyes of SkyNet: whenever you use a Crazy-Hi-Tech Gizmo, it is as though you are attempting to Act Under Fire, but instead of rolling +Cool you roll -Power (i.e the more powerful the gewgaw is, the more likely it is for SkyNet to notice it and get pissed).
That way, you have both a carrot and a stick. You've got these weird, characterful, hyper-advanced gizmos that provide a concrete mechanical benefit, which makes players want to use them. But they are unpredicatable and liable to bring down the wrath of SkyNet upon you. Or maybe not, because the MC has so many options on a partial hit or a clean miss. Either way, it will make players think twice about just whipping out their magic macguffin every time they want to Go Aggro on some poor sucker.
And because an example is worth a million words, how might this work in practice? Say I have one of these nifty sub-sonic dopamine actuators, +2 Power. And say I want to use it to help me convince Haemish to act as my bodyguard next time I make a foray into the Ash Wastes. I roll to Seduce or Manipulate (which is +Hot). I'm a crass, ugly motherfucker with a -1 Hot, so it's a good thing I've got this +2 gizmo, so I end up rolling +1. Depending on that roll Haemish may or may not help me out, the MC may or may not get to make an associated move, or whatever.
But once that is resolved, I make my Under the Watchful Eyes of Skynet roll, which is roll-Power. If I am super fly and roll a 12, I'm going to end up with a 10, in which case I escape unscathed. Heh.
If my final result is a 7-9, the MC is going to offer me a worse outcome, a hard bargain, or an ugly choice. In this case, maybe the MC says that once I get out into the Ash Wastes and start digging for hi-tech amongst the old ruins, SkyNet is able to triangulate on the signals that my gewgaw is using to pump poor Haemish full of good vibes and happy feelings, and jams them. Suddenly Haemish isn't feeling so good about being way out here in the Ash Wastes with just the two of us. And maybe he starts thinking he'll be better off making it back to the hold on his own. At some point, I look up from my digging and that fucker is just gone. So the "worse outcome" here is that sure, Haemish will accompany me out. But I'm on my own to get back.
Or maybe he offers me an ugly choice: sure, everything can go fine this time, but SkyNet is now on the alert for my particular Crazy-Hi-Tech Gizmo's unique signature and I'll take -1 forward on my next Acting under the Watchful Eyes of Skynet move. So I'll skate this time, but next time I am virtually guaranteed to have bad stuff happen.
And if my final result is a 6 or less, well, all of the usual MC moves are on the table, including taking away my stuff (SkyNet triangulates my Gizmo's signal and fries it with a 50 million volt pulse of microwave energy), inflicting harm (SkyNet figures out where the Gizmo is and starts dropping bombs on my head) or announcing future or off-screen badness (out in the Ash Wastes we see a bright flash and hear distant thunder. Huh, that's strange. But unbeknownst to us, SkyNet triangulated the location where the Gizmo was activated, which was my flophouse back at the hold, which is now a smoking crater.)
Also, because these are two separate moves, you have plenty of opportunities for hilarity (and moves snowballing). So I might completely flub when using the Gizmo and still bring down SkyNet's wrath. Or I might fail the first roll completely, have the MC take away my stuff (Haemish says, "I see what you're doing. Gimme that gizmo, you idiot"), then bomb the second roll as well and bring the wrath of SkyNet down on Haemish. Heh. Sucker.