Midst describes something that's among, in the middle of, or surrounded by. After the school talent show, your principal said he didn't know there were so many gifted singers in our midst.
Midst sounds a lot like mist, the fog that rolls in and can fill a place. Midst carries this same sense of being surrounded or placed in the middle of. It can be physical, like being in the midst of great athletes at the hockey game, or in regard to time, like the team captain breaking his foot in the midst of playoffs.