All of you people just need to wait until either the next episode or the episode afterwards. Next episode is probably going to be backstory on why mikasa is so infatuated with Erin.
I can't say any more without giving away a huge spoiler to the story.
I wouldn't say Mikasa is infatuated with Eren. More she's extremely attached to her family and afraid of loss.
Yeah, that's a much better choice of words. I was just in a rush to pick a word and get on with watching higurashi.