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.

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

5988. Some subordinates were once present with me close to my head. They talked as if they were asleep, yet they spoke perfectly well, as those do who are not asleep. I noticed that evil spirits were entering with obnoxious deceits into those subordinates, yet what went in was immediately dispersed. And because they knew that these same people had been their subordinates prior to that, they complained that they were no longer so. The reason they were no longer so was that good spirits could now act on them when they were asleep, so that this influx of the good spirits caused the obnoxious deceits of the evil ones to be dispelled. Even so the evil spirits were compelled to flow into these and no other subordinates. From this it is evident that subordinates vary in kind and nature and these variations exist as the Lord disposes.