This part is from Web Novel Arc 4 Chapter 34 [Ending World] and 35 [Girl's Gospel].
Long story short, he messed up in this loop again. Elsa suddenly appears in the mansion. Petra is killed, Frederica is presumed killed, and Subaru/Rem are about to be killed by Elsa.
Subaru enters Rem's room to attempt double suicide with Rem. But he is instead in Forbidden Archive, where Beatrice greets him.
[Beatrice : You're looking really bad, I suppose. Don't move and dirty the floor here...]
[Subaru : Open the door now! Let me out!]
[Beatirce : What can you do returning there? Betty don't understand what are you going to do with that wounds, I suppose.]
[Subaru : I know the best that I can't do anything! But! With door crossing activated, that murdering monster is going to! So!]
[Beatrice : It's already late.]
[Subaru : What... do you mean... late...]
[Beatrice : Your reason to return to that room is just gone, I suppose.]
Beatrice tries to heal his wounds, saying she doesn't care if Subaru dies or not, but won't stand seeing him die in her sight. Subaru struggles to reject her healing
[Subaru : I don't need healing! If you don't care me dying or not, why did you save me!?]
[Beatrice : That's because you look so bad and I didn't want to see...]
[Subaru : Why it was me!? If you were to help, and actually help, why didn't you save Petra or Frederica!? With your help, fighting or retreating, anything would have been possible! Saved! I was fool and pathetic, you could have done what I couldn't. Then, why...]
[Beatrice : Why should Betty do... Betty doesn't have reason to save those 3, I suppose. Don't know, I suppose. Doesn't care, I suppose.]
[Subaru : Then! You don't have a reason to save me, neither!? Why only me? What was difference between me and those 3! Rem was always kind, Frederica had so many wishes, Petra was too young! Everyone! Had more reasons, values! To live than me!]
[Beatrice : Value? Reason? Why should Betty respect those self-contentment, I suppose. Stop being full of yourself, I suppose, human.]
[Subaru : I don't care if this was whim of yours. If you have reason to save... and if you have any... kill me right now!]
[Beatrice : What... are you... saying...]
[Subaru : Kill me! Right now! Before everything is saved here, fixed here! Kill me!]
Subaru bites his tongue to commit suicide and lose consciousness, only sentence he barely heard was [Don't leave me...]
Waking up in the Forbidden Archive, Subaru first thought he made a return, but he notices his fingers gone and he haven't returned yet. To comforting Beatrice, he grabs Beatrice's dress and starts to pour his anger on her.
[Subaru : Do you understand what you did? Did I told you to save me!? Do you realize what you have done? You messed it all up! You've made it all gone! Why didn't you leave me to die! What could I do living like this! Helping on a whim, healing the wounds, are you satisfied!? Do you want to be thanked? Yes, thank you! I saved my life thanks to you! Saved my life when I lost every other thing!]
[Beatrice : Be...Betty... just... just...]
[Subaru : What? Are you satisfied with my gratitude? Stop looking down on me with that same leisurely face. Showing off? You really love it, don't you? belittling and sneering mere human...]
Subaru stops talking and release Beatrice from his grip when she started to cry, and realizes he have been pouring his rage onto wrong person, who doesn't know his 'Return by Death'.
Subaru apologizes her and try to leave the Archive and commit suicide out of her sight.
It is when he notices the black book dropped besides Beatrice.
Only same book he saw is the one Petelguese had (You could see it in Anime episode 15) and when he tries to reach it, Beatrice forcefully takes it, proving his worst expectation.
[Subaru : Why are you prizing it so much?]
[Beatrice : ...]
[Subaru : That's the book from Witch Cult, isn't it? It isn't, right? You just hid it because it could cause misunderstanding when it's that similar, right? I am easy to jump into conclusion, bad mouthed, angry look, bad personality...]
[Beatrice : ...]
[Subaru : Please, deny this for me.]
[Beatrice : What you imagined is true. This is the Gospel, same as the one Witch Cult has, milestone to the happiness, reason to live for, only truth, I suppose.]
[Subaru : How are you possessing one like that? Where do they sell? Lucky item foreseeing future is too much. Strategy guide for real life breaks the game... balance... hey...]
[Beatrice : Betty is not ordered to answer that question, I suppose.]
[Subaru : You can't do anything that isn't ordered by the book, do you?]
[Beatrice : That question isn't written on the book.]
[Subaru : What about healing my wound? Hiding me inside the library?]
[Beatrice : That question also isn't written on the book, I suppose.]
[Subaru : What about our discussion right now? Saving me from... death?]
[Beatrice : Don't know.]
[Subaru : You can't do anything that isn't ordered by the book, do you!?]
[Beatrice : Maybe, yes. Following anything the Gospel says, I suppose, is the sole reason of Betty's life. Betty exists only for that.]
[Subaru : You helped me because the book told you to do so? Saving me from the forest! Saving me from desperation! Even those happy times together! You're saying you didn't have any of your own will?!]
It is when Beatrice also shows anger against him.
[Beatrice : So... I'm saying yes, I suppose!]
[Beatrice : Everything Betty have done till now, is all written here, I suppose. You, mere you, cannot move Betty's heart, I suppose. Stop being full of yourself, human!]
[Beatrice : Betty have done everything expected for. Living only for that, waiting only for that, spenting only for that, and doing right now only for that. That... have been just denied by the likes of you!]
Beatrice uses her magic to get Subaru out of Forbidden Archive.
[Beatrice : Betty is all for mother! Connection to mother is everything to Betty! I don't care anything about you!]
After Subaru is gone, Betty quietly sits down and opens the Gospel with trembling hands.
[Beatrice : Why... Betty... doesn't have any...]
She sobs silently in front of the book, which has nothing written on it.
