By using this method you are giving yourself permission to banish all thoughts that are not directly related to technique from your mind. Dynamics, phrasing, style and even in some cases the notes themselves, can all be forgotten. The only thoughts in your mind should be technical considerations. If you are working on fingering then fingering should be the only thing that is in your mind at that time. Are you working on breathing? If so then that should be your only thought.
This practice technique can also be applied to your repertoire as well as your technical study material. When playing a piece of Beethoven for example, play it through with your mind and thoughts entirely on the fingering. Then play it though again this time focused only on breathing.