Page 300 of "The Big Red Book" in the chapter titled "Superiority of Atiyoga". Remember, he is not
discussing sutra here. He is discussing Dzogchen
and why it is superior to the lower 8 yanas.
Also worthy of note is the fact that he says that Nagarjuna/2nd Turning and Asanga/3rd Turning are both contained in Dzogchen. That is to be expected and does not negate my point. All Shentong view includes Nagarjuna. Elsewhere he explains that his interpretation of the 3rd Turning is "Great Madhyamaka" (a.k.a Shentong). Interestingly he includes the Dharmadhaturstava ("In Praise of Dharmadhatu") as one of Nagarjuna's. It certainly is not like Nagarjuna's other writings.
Now concerning this natural expression of the Great Perfection: The Sugata, during the intermediate promulgation of the transmitted precepts*, did not reveal the structure of the fundamental reality, though he did extensively teach the inconceivable, abiding nature without referring to symbols of elaborate conception. And, during the final promulgation**, though he did reveal the structure of the fundamental reality, he did not teach the characteristic path through which it is actualized. Therefore, the conclusive intention of the Two Promulgators*** actually abides without contradiction in the nature of the Great Perfection. This intention comprises the unaltered intention of the Collection of Madhyamaka Reasoning,, which consists of the commentaries on the intermediate promulgation by the sublime and supreme Nagarjuna; and his [Collection of Eulogies] including the Eulogy to the Expanse of Reality****, and the commentaries by the regent Maitreya, the sublime and supreme Asanga, and his brother [Vasabandhu] and so forth, which together form the intention of the final [promulgation]. If one were to ask why this is the case, it is because these masters did not claim anything other than the profound abiding nature of natural reality, and because the Great Perfection itself is none other than that.
So he says, "... during the intermediate promulgation of the transmitted precepts, did not reveal the structure of the fundamental reality
But he then say of Asanga/Vasabandhu, "....because these masters did not claim anything other than the profound abiding nature of natural reality...
So he accepts the 3rd Turning as being "profound abiding nature of natural reality, and because the Great Perfection itself is none other than that.
So Dudjom R. had no problem utilizing the 3 Turning paradigm to explain and define how Dzogchen is superior to the other yanas. Since he saw it as appropriate, so do I.
*a.k.a. The 2nd Turning of the Wheel of Dharma
**a.k.a. The 3rd Turning of the Wheel of Dharma
*** Nagarjuna and Asanga
****Available in English as "In Praise of Dharmadhatu"
All this is in regards to Dudjom R's interpretation of Dzogchen. Evidently he is an outlier in this among Nyingmapas. However Kongtrul also has a Shentong view of Dzogchen, and he is not an outlier among Karma Kagyupas. So at least one major school supports that idea within the context of Dzogchen specifically.
I support Mingyur R and HHDL in their positions against Lama abuse.