Great reaction, yes this one was deep... Mikasa's backstory was a lot to digest. Eren has been such a big influence on her life, it really comes full circle when you look at how loyal she is to him and always has his back, the way he did way back then, from not only fighting for her but then giving her the scarf and welcoming her as family. I personally feel like in her mind Eren is the only family she has left and she wasn't strong enough to fight for her first family at the time, but Eren helped her find her strength and she'll do whatever she can to protect her family now and others with now being a solider.
Armin is sort've the opposite, he isn't as strong as Mikasa, but Eren has always been there for him, to fight off his bullies and lift him up when he's down, Eren was also an inspiration for Armin to become stronger, and to become a soldier, but to see his inspiration and his friend eaten in front of him was a breaking point for Armin, his trauma didn't make him stronger in that moment like it did with Mikasa and her childhood trauma, it honestly made him more vulnerable it seems as he can barely stay in touch with reality because he is so traumatized. This episode is just so chilling