She drops the hammer, acting startled at the swipe. "No one... until now." she replies, swinging with the edge of the shield at her immediate assailant, while trying to figure out who this helper is.

The punch is a ruse. She's the wielder of Mjolnir, and just as it any other worthy to hold it, it returns at her call. A call she keeps silent, trying to have the hammer slam into the Panther's back as she's keeping him occupied. A tactic she knows Thor has used a time or three.