We sensed a traitor 'in our midst'. [=we sensed that one of the people in our group was a traitor]
He stood 'in their midst' [=he stood among them], waiting for a reply.
The region is currently 'in the midst of' a terrible drought.
(..) Jedi the Stallion. Checkmate again. Sorry, bro. Good game, my bro. Looks like we got another Dark Horse in our midst, eh? What Dark Horse? Him? - Didn't you go crazy or something? - Michael. You made a mistake. What, winning? (..)2014 The Dark Horse