Verse 10

10.  Even in the waking state,  again,  what is imagined by the mind within is verily non existing;   what is apprehended by the mind outside is existing the unreality of these two ought to be held to be likewise reasonable.

"Even in the waking state,  again,  what is imagined by the mind within is verily non existing"

Considering just the waking state,  within which people imagine that reality or true existence is genuinely perceived,  people may think of an object of pleasure or fear but know it to be unreal only because it is seen within their mind.

"what is apprehended by the mind outside is existing"

That same person,  after seeing imaginary objects within their mind,  may see through their sense of vision a car.  That person will ascribe true existence to the car because it is perceived as being in the  "real world"  outside the mind.

"the unreality of these two ought to be held to be likewise reasonable."

"these two",  within the mind and external to the mind,  should both be seen as unreal,  Gaudapada asserts.  The logic is,  what is perceived within the mind is generated by the mind from memory in consciousness.
What is perceived external to the mind is again generated by the mind from sense information in consciousness.
Both conscious acts were achieved within the same conscious  "waking state".  any of the three  "conscious states",  as it were,  of waking,  dreaming,  or sleeping have been thoroughly shown to be unreal,  a delusion of duality.  So,  as stated in this verse,  "the unreality of these two ought to be held to be likewise reasonable".