"I fooled my comrades": *thinks about Levi in particular*
"Someone I can bring back": *thinks about Erwin only*
Erwin, as he reflects on his burning desire to see the basement and the lives he had to sacrifice, admits that he deceived his comrades—yet it is Levi who comes to his mind.
Levi, when he wonders whether there might still be someone alive to inject with the serum, thinks only of Erwin; that “someone” narrows down to Erwin alone.
This parallel shows, to me, how deeply they were rooted in each other’s heart and mind.
It’s details like these that make me love you, Eruri ♥️