it ruined the moment. in the anime he cries boom flashback boom he bites his hand. in the manga he gets grabbed has a flashback and is furious asf and turns which was way better imo but whatever
Everything would've been over if he just went with them. Although that it is true, it is difficult to do so when these people caused the deaths of hundreds and pain and suffering of hundreds of thousands.
Umm because everybody looks up to Reiner, he was like a big brother to him and everyone, Bert too. Not to mention they are the reason his mom is dead.
All of this happened in a matter of minutes in his head then made the decision to kill them both, Eren will not look back after that. I think the anime did a great job with it.