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)

6192. I have been shown by live demonstration the manner in which spirits flow in with a person. When they come to him they adopt everything his memory contains, thus everything he has learned and retained since early childhood. Then the spirits suppose that what they have adopted is their own and thus play the part so to speak of the person in the person; but they are not allowed to go beyond the interior parts forming the person's thought and will. They are not allowed to enter the exterior parts of actions and speech; for these are brought into play by means of a general influx from the Lord, without the intervention of specific spirits or angels. But although the spirits play the part of the person in the person so far as what forms his thought and will is concerned, they are not actually aware of their presence with him. The reason for this is that they take possession of all that his memory contains and imagine that it does not belong to another but is their own. A further reason is that they are thus prevented from doing the person harm, for if the spirits from hell who are present with a person did not imagine the contents of his memory were their own they would try by every method to destroy the person, body and soul, since that is hell's essential delight.