Once Subaru could tell that they were done doing that with Cor Leonis, he went to talk to Rem.
"Hey, Rem there's something I need to ask you."
"Oh um, what is it?" Rem's face was red, and she was looking down. Subaru could tell that she was ashamed of herself for what she and Emila had done with Roswaal.
"I'll tell you later, I want to find Emilia-tan first, I want to talk to the both of you."
Subaru was able to find Emilia easily using Cor Leonis, although she kept on trying to avoid him. He could tell that she was also ashamed of what she had done. Eventually he was able to get the two of them together.
"Emilia-tan, do you remember when we went to the Pleiades Watchtower? There's something I have to do there and I want the two of you to come along with me." When he said that, both Emilia and Rem relaxed. When he said that he had wanted to talk to them, they both got very nervious and tense. They had probably thought that he was going to confront them about what they had done with Roswaal.
"Okay, that sounds like it could be fun, what do you need to do there?" Emilia asked
"Ah, it's nothing. I'll tell you when we arrive there."
So they left to go to the Pleiades Watchtower, Subaru dealt with the Mabeasts using his authority of gluttony, which allowed him to control Mabeasts like Meili.
During the trip Subaru could tell that both Rem and Emilia felt guilty for what they did. They often avoided looking at him in the eye and sometimes he could hear them crying in shame.
He still didn't understand why they felt guilty, it was all his fault for not being like [Natsuki Subaru]. Even now, he could do nothing to help them with their guilt since they were avoiding him.
Eventually they arrived at the Watchtower, and Subaru was having second thoughts. Could he really bring himself to kill the two women he loved, even if their deaths were temporary.
[Natsuki Subaru] wouldn't have been able to do such a thing. [Natsuki Subaru] had promised to value his life more and not throw it away or use loops to gather information like Subaru was planning to do.
But it was necessary, he had to do this. He had to.
"I have to do this, I have to become like [Natsuki Subaru] so that I can make everyone happy." Those were Subaru's thoughts
"I have to do this. I have to do this. I have to do this. I have to do this." Subaru kept on muttering to himself
"Subaru, are you okay? You've been acting reealy weird." Emilia was concerned for Subaru as they got closer and closer to the Watchtower, Subaru started acting weird. Both of his wives were concerned for him.
"I'm sorry! I'm sorry!" Subaru ran away and ordered all the Mabeasts in the area to attact Rem and Emilia. He didn't look back when he heard their screams, but he was tempted to just kill himself and bring them back.
"I had to do it! I had to do it! I HAD TO DO IT! I HAVE TO BE LIKE [Natsuki Subaru]!" Subaru kept on saying to himself.
Eventually he arrived at the Taygeta library, he found both Rem and Emilia's books. Subaru was nervious, but he had to do this, or else this trip would have been a waste. Their lives would have been lost for nothing.
Subaru mentally prepared himself, and opened the books.