The "midst" of something in the Bible represents the thing that is most central and most important to the spiritual state being described, the motivation that drives everything else. In general this will be something we love or feel, because at the core of things we are what we love; our loves define us.

(Odkazy: Apocalypse Revealed 44, 90, 268; Arcana Coelestia 2252, 2940, 10153, 10365, 10557, 10635, 10641)

7653. 'How long will this thing be a snare to us?' means that by behaving in that way they would be held captive by their own evil. This is clear from the meaning of 'this thing being a snare' as being held captive by their own evil, and so being led into the misery that punishment brings.