You're problematic soldier and Captain Levi's responsible for you so he must always catch you or talk. He can punish you, everyone are saying that he must do it, but although he's cold and rude, he never did this and he doesn't want. He knows you'll be more problematic, that's why he just talks to you and don't punish you. Or mabye he feels something more towards you?

Captain Levi: Can you tell me why you hit Petra? We're soldiers and you can't just hit someone who is with you in my squad.