The phrase "back even deeper" is grammatically correct and usable in written English
You can use this phrase to describe a situation in which something continues to deeper or further levels. For example, "We have delved into the mystery further and further, back even deeper than we thought possible."
The Germany-based medieval-music ensemble Sequentia takes you back even deeper into the mists of time; its CD "Edda," on the Deutsche Harmonia Mundi label, re-creates the chanted recitations with which Icelanders once whiled away the dark winter months.
Further, the general concept of contact with a toxic agent can be traced back even deeper into the history of occupational medicine, with the qualitative aspects of exposure being traceable to the treatise De Morbis Articum written by Ramazzini in 1688 (Lioy 2007; Ramazzini 1964).
Then, when you're putting the zombie makeup on, shadow the wrinkles with a light makeup brush so when you step back, they look even deeper.
However, DeBroglie, Bohm and others (even for a time Einstein) tried to reinstate determinism by moving it back to an even deeper fundamental level via hidden variable theories.
Young added: "And if I ask her to give them back I will be in even deeper trouble".
And while we will still sometimes falter, and stumble, and even fall, the excitement of the ride is usually enough to get us back into the game with an even deeper embrace for the infinite variety of life.
Even deeper trends, going back decades to the rise of pro-business, anti-regulation lobbyists and the decline of unions, as recounted in Timothy Noah's book on income inequality, The Great Divergence, helped shape the decline of the middle and working class in America, laying the groundwork for disenfranchised whites to be Trump's key base of support.
When I complimented Mr. Kovach on his metaphoric shovels, he smiled and pointed to a set of bright red children's snow shovels in the back room, sitting ready for an even deeper plunge into literary texts and the larger social questions these readings evoke.
Step back, though, and you can see an even deeper problem: the implicit conflation of the production of things with the living of a creative life.
With no way back to the human world, Dante heads even deeper into the demon world on his motorcycle.
Demand your back-end money and you're in even deeper trouble, as New Line's former favourite, Peter Jackson, is now discovering.
