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.

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

2451. 'And all the inhabitants of the cities' means that all goods were severed from them so that they might possess nothing but evils. This is clear from the meaning of 'the inhabitants' when they are those of a city, as goods - as may be confirmed from many examples in the Word. This meaning is also evident from the fact that when 'a city' means truth, as has been shown, 'inhabitant' means good, for it is truth that good inhabits. But truth in which there is no good is like an empty or uninhabited city. That in addition to this all goods as well are separated from the evil so that they possess nothing but evils, see above in 2449.