Does the illusion described in the spell mental prison extend to the space above the target creature?

Question

The description of the mental prison spell reads:

you make the area immediately around the target’s space appear dangerous in some way. (XGtE, pg. 161)

And the spell’s 10d10 damage triggers when,

the target is moved out of the illusion...or reaches any part of its body through it.

It seems this can be interpreted to mean the illusion appears on all sides around the target and not necessarily above the target. Can a creature with immunity to restrained and a flying speed avoid the 10d10 damage by flying up and out of the illusion?

Here is a list of creatures with immunity to restrained and a flying speed.

Answer 1

Yes, the dangerous area includes above and below

The spell's description says:

... you make the area immediately around the target’s space ...

Around would include all sides, including above and below, since it does not in any way limit the meaning of "around" in the spell's description. If a creature flew up or burrowed down to escape the illusion, it would appear there too, and moving through it would incur the same penalties as moving through it horizontally.

This is also consistent with the spell's name, mental prison, since prisons are things you aren't supposed to be able to escape from, so it would be rather unintuitive if they could quite easily escape from said prison by simply moving vertically.