Act under Fire and internal fire

I'm not sure I understand perfectly the rules and their spirit, here. For external fire, it's pretty clear :
When trying to be sneaky, the fire is you are discovered, if you miss you are discovered.
When running in the middle of a battle, the fire is you get hurt, if you miss you certainly take Harm.
When defusing a bomb, the fire is the bomb explode, if you miss you certainly take Harm.
etc.

But when the fire is internal (self-loathing, culpability, respect for life), what is the result of missing the roll, beyond not making the action.
When trying to betray a friend, the fire is your culpability, what happens if you miss ?
When trying to kill an innocent, the fire is your respect for life, what happens if you miss ?
When trying to go against a Manipulation attempt, the fire is you deny the leverage, what happens if you miss ?
etc.

What are your MC moves and threat moves?

Anytime the question is what happens, especially on a fail, you make a hard move and misdirect.

Yeah, a partial hit or a miss allows the MC to make some kind of move.

However, the move doesn't have to be an obvious result.  The "fire" that you're referring to, is whether or not you pull off whatever it is you are going to do.  If you fail or partially hit that roll, then the MC can make a move stemming from this, that complicates the situation, and the move should be supported by what makes sense in game.  With sneaking, the Fire isn't necessarily getting caught.  It can be a bunch of things. 

For example, if JC is sneaking by Parcher and his cannibals (grotesque: Cannibal), a miss means that I can do one of the moves, and it can take a variety of forms.  Here's a few examples:

The cannibals cut off JC's avenue of escape (Putting him into a spot).
The cannibals drag JC's girl Amy into their camp and begin slathering her with barbecue sauce (Capture someone).
JC is distracted by the sound of an intense gunfire as it echoes from somewhere up near the Holding "Six Blades" (Announce off-Screen Badness).
JC sees that the cannibals have a rough map of the nearby Holding "Six Blades", and are discussing weak points they can take advantage of. (Announce future badness)

And that's just from the standard moves.  From the Grotesque moves, there's a choice of more moves I can make:

JC stumbles into the garbage pit, filled with the gruesome remains of the people eaten by the cannibals. (display the nature of the world it inhabits)
JC is surprised by a skulking cannibal, who stabs at his back with a steak knife. (Attack someone from behind or otherwise by stealth)
JC is discovered by Parcher's head cook, but told he can leave without further discovery if he "Just takes a bite from the main course, let me know if the meat's nice and tender".  (Offer something to someone, with stings attached)

Again, there's lots of possible consequences, and they all stem from the moves available.  Just remember to scale the awfulness of the move appropriately, a partial hit means a partial success.  Sometimes the urge is to treat a partial hit like a full on failure, and that shouldn't be the case.