Mikasa is faster than him or most people anyway, not that she is surprised at all by Eren running after the kid first. He is always running somewhere, hopefully not anywhere where she couldn't follow here.

Oh he should definitely check that Mikasa doesn't have a fever, this one seems like it could be the worst fever ever!! Maybe he should also make sure that she gets some rest, who knows.

"Okay. I'll be back soon." Her hands let go of him really slowly, hesitantly as if Eren might be the one disappearing next if she lets go and goes somewhere now. She gives an accidentally scary look to the other two because they should be nice to Eren while she'll go...

And there she goes, running silently after the kid and leaving him to deal with the other two, who are hopefully still there and behaving nicer than that third one??