That is not so, since it is impossible for the mental consciousness to arise in dreams. So,
Just like for you externals are not there
In dreams, the mind as well is not produced.
Hence,
All three, the eye, the object seen, the mind
Which they engender, each of these are false. (6.51)
The perception of forms happens when the eye, the form and the mind are in proximity. Likewise, when objects are distinguished in dreams, a coming together of these three is observed. And just as in that context eyes and form are found to be non-existent, eye-consciousness too has no existence. And just as with these three, the same is the case for the rest:
The rest, with ears and such, are unproduced.
The words ears and so forth include the rest, from sound and ear consciousness up to and including mentation, mental phenomena and mental consciousness. Thus, since all of these triads are false within the dream, it makes no sense to say that the mental consciousness exists in dreams.
Some think that, ‘The form apprehended by the mental consciousness belongs to the sense field of mental phenomena, and does exist in the dream. Hence, it is not at all the case that consciousness exists without objects.’ But this sentiment is also unreasonable, since the three are utterly unfeasible in dreams. If they say they have accepted this in order disprove the scriptural tradition of the others, the dream example becomes meaningless, because what is deemed not false cannot serve to illustrate things that are considered false.