I have an ambiguous script situation, 2 co-protagonists begin gaslighting the MC. They each have ulterior motives which they don't say. The reader is intended to infer the lies through contradictory statements, and the abrupt character change. The shift is so extreme it calls into question everything that has come before, and the MC is overwhelmed by the double-whammy. All 3 characters are on a negative arc. There's no reconciliation. It ends dark.
To clarify gaslighting refers to the 2 characters independently lying to the MC to discourage or discredit her. In my story the Hero is gaslighting for sinister reasons (to cover up that he assaulted her), the Paragon is gaslighting to scare the MC so she will get away. The gaslighting dialog has enough truth mixed in to be plausible, in some cases explaining hanging mysteries, or adding a twist that changes them. This is the emotional climax that pushes everyone to their ending state.
The Hero's downfall has been heavily foreshadowed, and the MC has been his foil and antagonist – it's why she is assaulted. I have a good idea how this plays out. They argue, and within this dialog the MC calls out his hidden agenda. Then we see the assault which he later gaslights about, so it's clear.
But almost immediately comes the Paragon's gaslighting in reaction to this assault, and this motive is much harder to show the reader.
The Paragon's gaslighting is basically victim-blaming, and the "twist" aspect suggests the Paragon has been expecting it since the beginning. It causes the MC to leave (it's important that she does). There's no apology, and they don't speak again. There is no "witness" character to observe, or a confidant to confess it to.
I originally wrote the Paragon's scene as another confrontation, with the MC saying "You are gaslighting me, blah-blah-blah", but that was too on the nose, too similar to the confrontation with the hero, and she can't be devastated if she also announces she can see through the ruse.
So I removed the explanation. The Paragon is stoic with a few cracks to show inner-turmoil/regret, but mostly relying on the reader to recognize this is out-of-character – except, since I just made the hero assault the MC, the Paragon could be a cruel manipulator in a surprise grimdark ending.
How do I show that the Paragon is "wounded" by this act of tough love? Or at least justify it as a strategic maneuver (in-character for the Paragon)? It's not important that the MC understands the motive at all. My concern is the reader.