Yoooo I'm glad that you appreciate how good Roswaal is as a character. The insanity of trying to use Subaru's ability so that a "different Roswaal" can achieve his goal is just....next level.
Also in episode 12 it isn't fully conveyed how hard the second trial was for Subaru. The guilt and horror of leaving all of those timelines behind was unbearable for him. It was basically his worst nightmare come true: RBD only saves himself but the others still die or suffer the consequences in a different world. He was truly on the verge of going insane and his soul being ripped apart.
Of course later in Ep 12 Echidna clarifies that its only a possibility: RBD may create new timelines or it may just rewind time for the current one. Subaru obviously has to hope that the latter is the case for his own sanity.
Anyways great reaction mate thx for uploading