Erens plan to save his friends seems to contain a glaring plot hole yet that plot hole actually makes sense. Attack on Titans protagonist Eren Jaeger transforms into the animes largest villain in season 4 as he plans to wipe out all of humanity beyond his homeland Paradis Island. Eren conceals his motives from his best friends and brother Zeke Jaeger as he plots to take the fate of the world into his own hands. Attack on Titan episode 87 consolidates that the motivation for Erens genocide plan is purely to ensure his friends safety however his plan puts his friends in mortal danger as they are attacked by hordes of titans.
This plan forces Mikasa Armin and co. to wonder which side Eren is really on. Once Eren gains the power of the Founding Titan he can control the wall titans and march them across continents to wipe out humanity yet the titans inside the walls still try to eat the people within the walls. This rightly leads Armin to question If Eren commands the Founder cant he control every titan? It is bizarre that in Erens attempts to save his friends he also endangers them.This plot hole makes sense however because Eren specifically left Mikasa with the rest of the scouts. Even though Mikasa and Eren have been bonded since birth in Attack on Titan episode 73 Eren tells Mikasa that he has always hated her. Erens plan to save his friends proves that this is not true but he is this harsh towards her to ensure that she does not prioritize his safety over the safety of everyone else. Eren is aware that even if his plan puts his friends in danger Mikasas capabilities will ultimately guarantee that they are all safe and capable of moving on without him.
Eren proves throughout Attack on Titan that he is capable of making difficult choices that others cannot hence why he is now considered the main villain as the anime hurtles towards its conclusion. Telling Mikasa that he hated her due to her subservience is one such choice. This apparent revelation leads Mikasa to side with the scouts and the alliance that intends to stop Eren the villain. Eren believes that his other friends need Mikasa more than she does since she is the best fighter against titans. She masters using ODM gear straight away and after Levi is injured after his run in with Zeke she is the scouts best hope of survival. Mikasa proves her abilities numerous times throughout the series and when the titans attack the scouts after Eren enacts the Rumbling she demonstrates her abilities again by saving Yelena from certain death.
Ensuring that Mikasa is with the scouts instead of himself arguably increases the chances of the Rumbling succeeding. Although Mikasa is one of humanitys greatest fighters and could potentially kill many of Erens titans she is also the one person that could dissuade Eren. It appears that no one is capable of changing Erens mind about his genocide plan but if anyone can it would be Mikasa as she grew up with Eren and is who he cares most deeply about. Erens cruelty towards Mikasa could also be an attempt to sever her bond to him especially if Erens plan is unsuccessful. Eren is aware that he has a finite amount of time before he dies and therefore wishes for Mikasa to be happy when he dies. Erens lie could be his most loving act since it is an attempt to help Mikasa and his friends to live contently to be able to move on regardless of what happens to him. The supposed plot hole is evidence that Eren wants his friends to grow less attached to him and to shed their burden of friendship. Whether or not they will stop Eren or join him will be revealed in Attack on Titan season 4 part 3.