Levi has always recognized Mikasa’s abilities, trusted her enough to place her next to him in missions, and the way I see it, treated her a bit differently than the other squad members! – it could be because Mikasa proved herself reliable or because he saw a piece of him in her, or it’s just a feeling of whatever is this thing that relates them.. or all of this!-.
(for one .. she’s definitely his protégée! )
I always found it funny that whenever Mikasa retorted on Levi roughly he never gets mad or give it much thought.. like Yo I’m your captain where’s manners!
If anything he makes sure to explain things or clear his idea.